(a)  A crescent-shaped, concave or linear mark on the face of a bluff or valley wall, produced by the lateral erosion of a meandering stream which impinged upon and undercut the bluff; if it's no longer adjacent to the modern stream channel it indicates an abandoned route of the stream.  SW;  (b) (not recommended - refer to oxbow)  An abandoned meander, commonly filled in by deposition and vegetation, but still discernible.  GG
(a)  An end moraine that contains numerous kames.  (b)  A group of kames along the front of a stagnant glacier, commonly comprising the slumped or erosional remnants of a formerly continuous outwash plain built up over the foot of rapidly wasting or stagnant ice.  GG
(a)  Any long, narrow depression in the earth's surface, such as one between hills or with no surface outlet for drainage.  (b)  (not preferred - see U-shaped valley,  mountain valley)  A broad, elongate U-shaped valley, such as a glacial trough.  Compare - U-shaped valley.  GG
(a)  Drainage basin;  (b) A low area in the Earth's crust, of tectonic origin, in which sediments have accumulated.  GG  (c) (colloquial:  western USA)  A general term for the nearly level to gently sloping, bottom surface of an intermontane basin (bolson).  Landforms include playas, broad alluvial flats containing ephemeral drainageways, and relict alluvial and lacustrine surfaces that rarely, if ever, are subject to flooding.  Where through-drainage systems are well developed, flood plains are dominant and lake plains are absent or of limited extent.  Basin floors grade mountainward to distal parts of piedmont slopes.  FFP
(a)  Human-constructed deposits of natural earth materials (e.g. rock, soil, gravel) and waste materials (e.g. tailings or spoil from dredging) used to fill a depression, to extend shore land into a a body of water, or in building dams.  (b)  Soil or loose rock used to raise the surface level of low-lying land, such as an embankment to fill a hollow or ravine in road and railroad construction
(a) (colloquial - northeast USA) A narrow passageway, or short defile between mountains; a deep, close pass.  Compare - gap.  (b) A breached opening in the rim of a volcanic crater.  GG
(a) (colloquial: western U.S.A.)  A nearly level, graded, alluvial surface in bolsons and semi-bolsons that lacks distinct channels, terraces or floodplain levels.  Compare - flood-plain step, terrace, valley flat.  FFP, GG, & SW.  (b) (not preferred) A general term for a small flood plain bordering a river, on which alluvium is deposited during floods.  GG
(a) (not preferred - see hillock) An imprecise, general term for a rounded or conical mound or other small elevation.  (b) (not preferred) A slight rise of ground above a level surface.  GG.
(a) (not preferred- refer to rotational slide) A generic, obsolete term for various types of landslides, especially rotational landslide; the process, associated sediments, or resultant landform characterized by a slide involving a shearing and rotary movement of a generally independent mass of rock or earth along a curved slip surface (concave upward) and about an axis parallel to the slope from which it descends, and by backward tilting of the mass with respect to that slope so that the slump surface often exhibits a reversed slope facing uphill.  Compare - rotational slide, slide, landslide.  SW, GG, & DV.  (b) (not recommended) refer to rotational slide.  An informal term for the landform or mass of material slipped down during, or produced by a landslide.  GG & DV
(a) [stream] The hollow bed where a natural body of surface water flows or may flow.  The deepest or central part of the bed of a stream, containing the main current and occupied more or less continuously by water.  (b) (colloquial: western U.S.A.) The bed of a single or braided watercourse that commonly is barren of vegetation and is formed of modern alluvium.  Channels may be enclosed by banks or splayed across and slightly mounded above a fan surface and include bars and mounds of cobbles and stones.  (c) [microfeature] Small, trough-like, arcuate or sinuous channels separated by small bars or ridges, caused by fluvial processes and common to floodplains and young alluvial terraces; a constituent part of bar & channel topography. GG, FFP, & SW
(a) A bank, mound, or other artificial accumulation composed of spoil;  e.g., An embankment of earthy material dredged from a channel and deposited alongside it.  (b) A pile of refuse material from an excavation or mining operation; e.g. a pile of dirt removed from, and stacked at the surface of a mine in a conical heap or in layers.  GG
(a) A category of mass movement processes, associated sediments (fall deposit), or resultant landforms (e.g., rock fall, debris fall, soil fall) characterized by very rapid movement of a mass of rock or earth that travels mostly through the air by free fall, leaping, bounding, or rolling, with little or no interaction between one moving unit and another.  Compare - topple, slide, lateral spread, flow, complex landslide, landslide.  SW & DV;   (b) The mass of material moved by a fall.  GG
(a) A divergent stream flowing away from the main stream and not returning to it, as in a delta or on a flood plain.  It may be produced by stream deposition choking the original channel.  (b) One of the channels of a braided stream; a channel carrying the water of a stream distributary.  GG
(a) A general term for a course or channel along which water moves in draining an area.  GG;   (b) [soil survey] a term restricted to relatively small, roughly linear or arcuate depressions that move concentrated water at some time, and either lack a defined channel (e.g. head slope, swale) or have a small, defined channel (e.g. low order streams).  SW
(a) A general term for a natural, freshwater surface stream of considerable volume and generally with a permanent baseflow, moving in a defined channel toward a lake, sea, or a larger river;  (b) (colloquial - New England, USA; not recommended)  A small watercourse which elsewhere in the USA is known as a creek.  Compare - stream.  GG
(a) A gently sloping zone of unconsolidated material, typically with a concave profile, extending landward from the low-water line to the place where there is a definite change in material or physiographic form (such as a cliff) or to the line of permanent vegetation (usually the effective limit of the highest storm waves); a shore of a body of water, formed and washed by waves or tides, usually covered by sand or gravel; (b) the relatively thick and temporary accumulation of loose water-borne material (usually well-sorted sand and pebbles) accompanied by mud, cobbles, boulders, and smoothed rock and shell fragments, that is in active transit along, or deposited on, the shore zone between the limits of low water and high water.
(a) A gently sloping, fan-shaped mass of detritus forming a section of a low-angle cone commonly at a place where there is a notable decrease in gradient; specifically an alluvial fan (not preferred - use alluvial fan). Compare - alluvial fan, alluvial cone.  (b) A fan-shaped mass of congealed lava that formed on a steep slope by the continually changing direction of flow.  GG
(a) A high bank or bold headland, with a broad, precipitous, sometimes rounded cliff face overlooking a plain or body of water, especially on the outside of a stream meander; ex. a river bluff.  (b) (not preferred) use cliff.  Any cliff with a steep, broad face.  GG
(a) A lake occupying a deflation basin as in a blowout on a dune.  (b) A lake occupying a basin formed by the blocking of a stream by sand dunes migrating along a shore (e.g. Moses lake, WA).  GG
(a) A lake that derives much or all of its water from the melting of glacier ice, fed by meltwater, and lying outside the glacier margins (e.g. proglacial lake) or lying on a glacier (e.g. ice-walled lake, ice-floored lake) and due to differential melting.  (b) A lake occupying a basin produced by glacial deposition, such as one held in by a morainal dam.  (c) A lake occupying a basin produced in bedrock by glacial erosion (scouring, quarrying); e.g., cirque lake, fjord.  (d) A lake occupying a basin produced by collapse of outwash material surrounding masses of stagnant ice.   GG
(a) A landform that consists of a wave-cut scarp and wave-built terrace of well-sorted sand and gravel of marine and lacustrine origin. (b) (colloquial: western U.S.A.) relict shorelines from pluvial lakes, generally restricted to valley sides.  Compare - strandline, shoreline.  FFP
(a) A low, rounded natural hill, of unspecified origin, generally less than 3 m high, composed of earthy material; Compare - hillock.  (b) A small, human-made hill, composed either of debris accumulated during successive occupations of the site (e.g. tell) or of earth heaped up to mark a burial site (e.g. burial mound).  (c) A structure built by colonial organisms (e.g. termite mound).  GG
(a) A narrow shelf or projection of rock, much longer than wide, formed on a rock wall or cliff face, as along a coast by differential wave action on softer rocks; erosion is by combined biological and chemical weathering.  (b) A rocky outcrop; solid rock.  (c) A shelf-like quarry exposure or natural rock outcrop.  Compare - structural bench.  GG
(a) A narrow, deep valley with nearly vertical, rocky walls, smaller than a canyon, and more steep-sided than a ravine; especially a restricted, steep-walled part of a canyon.  (b) A narrow defile or passage between hills or mountains.  GG
(a) A narrow, elongate, coarse-textured, intertidal, sloping landform that is generally parallel with the beach ridge component of the barrier island, or spit and adjacent to the ocean.  Compare  barrier island.  (b) [relict] (colloquial: western U.S.A.) A wide, gently-sloping portion of a bolson floor comprising numerous, parallel, closely-spaced, relict longshore-bars and lagoons built by a receding pluvial lake.  Synonym, offshore barrier, offshore beach, bar beach.  Compare - bar [coast], barrier island.  GG and FFP.
(a) A rounded eminence, a small hill or mountain; especially a prominent or isolated hill with steep sides, commonly found in the Southern United States.  (b) A peak or other projection from the top of a hill or mountain.  Also, a boulder or group of boulders or an area of resistant rocks protruding from the side of a hill or mountain.  GG
(a) A seaward end or the widened funnel-shaped tidal mouth of a river valley where fresh water comes into contact with seawater and where tidal effects are evident; e.g., a tidal river, or a partially enclosed coastal body of water where the tide meets the current of a stream.   (b) A portion of an ocean or an arm of the sea affected by fresh water.   (c) A drowned river mouth formed by the subsidence of land near the coast or by the drowning of the lower portion of a non-glacial valley due to the rise of sea level.  Compare-lagoon.  GG
(a) A shallow, open depression in unconsolidated materials which lacks a defined channel but can funnel overland or subsurface flow into a drainageway.  Soils in swales tend to be moister and thicker (cumulic) compared to surrounding soils.  SW  (b) A small, shallow, typically closed depression in an undulating ground moraine formed by uneven glacial deposition; Compare - swell-and-swale topography.  (c) (not preferred; refer to interdune)  A long, narrow, generally shallow, trough-like depression between two beach ridges, and aligned roughly parallel to the coastline.  GG
(a) A shallow, open depression in unconsolidated materials which lacks a defined channel but can funnel overland or subsurface flow into a drainageway.  Soils in swales tend to be more moist and thicker (cummulic) compared to surrounding soils.  SW  (b) A small, shallow, typically closed depression in an undulating ground moraine formed by uneven glacial deposition; Compare - swell-and-swale topography.  (c) (not preferred; refer to interdune)  A long, narrow, generally shallow, trough-like depression between two beach ridges, and aligned roughly parallel to the coastline.  GG
(a) A small marsh, especially a marshy area lying in a local, shallow, closed depression on a piece of dry land, as on  the prairie of the midwestern U.S.A.  (b) A term used, especially in the Mississippi Valley, for a creek or sluggish body of water in a tidal flat, flood plain, or coastal marshland.  Compare - bayou, oxbow.  (c) A sluggish channel of water, such as a side channel of a river, in which water flows slowly through low, swampy ground, as along the Columbia River, or a section of an abandoned river channel which may contain stagnant water and occurs in a flood plain or delta.  (d) (not preferred) An area of soft, miry, muddy or waterlogged ground, a place of deep mud.  GG
(a) A small point or low tongue or narrow embankment of land, commonly consisting of sand or gravel deposited by longshore transport and having one end attached to the mainland and the other terminating in open water, usually the sea; a finger-like extension of the beach. (b) A relatively long, narrow shoal or reef extending from the shore into a body of water.  GG
(a) A steep slope or cliff formed by differential erosion along a fault line, as by the more rapid erosion of soft rock on the side of a fault as compared to that of more resistant rock on the other side; e.g. the east face of the Sierra Nevada in California.  (b)  (not recommended) A fault scarp that has been modified by erosion.  This usage is not recommended because the scarp is usually not located on the fault line.  GG
(a) A type of tropical karst topography characterized by isolated, steep-sided, residual limestone hills or ridges with vertical or near-vertical walls, and may be relatively flat-topped; commonly surrounded by a flat alluvial plain or lagoons.  (Also called fenglin).  (b)  A cluster of peaks or ridges with vertical or near-vertical walls, and convex upper side slopes where towers rise from a common base and are separated by deep, rugged ravines or large sinkholes.   (Also called fengcong, turmkarst).  Compare - karst tower, cockpit karst, cone karst, fluviokarst, kegel karst, sinkhole karst.
(a) A vent in the surface of the Earth through which magma and associated gases and ash erupt; also, the form or structure, usually conical, that is produced by the ejected material.  (b) Any eruption of material, e.g. mud, that resembles a magmatic volcano.  GG '87
(a) An area of land completely surrounded by water;  (b) An elevated area of land surrounded by swamp, or marsh, or isolated at high water or during floods.  Compare - barrier island.  GG
(a) An elongate moraine carried in or upon the middle of a glacier and parallel to its sides, usually formed by the merging of adjacent and inner lateral moraines below the junction of two coalescing valley glaciers.  (b) A moraine formed by glacial abrasion of a rocky protuberance near the middle of a glacier and whose debris appears at the glacier surface in the ablation area.  (c) The irregular ridge left behind in the middle of a glacial valley, when the glacier on which it was formed has disappeared.  GG
(a) An elongated body or stretch of land nearly surrounded by water (e.g., on three sides) and connected with a larger tract of land area, usually by a neck or an isthmus.  (b) A relatively large tract of land jutting out into the water, with or without a well-defined isthmus; e.g., the Italian peninsula.  GG
(a) An informal, generic term for low-lying land or an extensive region of low-lying land, especially near a coast and including the extended plains or country lying not far above tide level.  (b) (not preferred) A genericvague, imprecise term for a landscape of low, comparatively level ground of a region or local area, in contrast with the adjacent higher country.  (c) (not recommended use valley, bolson, etc.) A generic term for a large valley.  Compare - upland.  SW
(a) An irregularity of land, especially of considerable height with a steep cliff face, jutting out from the coast into a large body of water (usually the sea or a lake); a bold promontory or a high cape.  (b) The high ground flanking a body of water, such as a cove.  (c) The steep crag or cliff face of a promontory.  GG
(a) Any body of running water that moves under gravity to progressively lower levels, in a relatively narrow but clearly defined channel on the ground surface, in a subterranean cavern, or beneath or in a glacier.  It is a mixture of water and dissolved, suspended, or entrained matter.  (b) A term used in quantitative geomorphology interchangeably with channel.  Compare - river.  GG
(a) Any small, externally drained V-shaped depression (in cross-section) cut or deepened by a stream and floored with alluvium, or a broader, U-shaped depression modified by an alpine glacier and floored with either till or alluvium, that occurs on a mountain or within mountains.  Several types of mountain valleys can be recognized based on their form and valley floor sediments (i.e., V-shaped valley, U-shaped valley).  Compare - valley.  SW (b) (colloquial: Basin and Range, USA)  A relatively small, structural depression within a mountain range that is partly filled with alluvium and commonly drains externally to an intermontane basin, bolson, or semi-bolson.  Compare - valley flat.  SW &  FFP
(a) Any terrestrial formation resembling a bay of the sea, as a recess or extension of lowland along a river valley or within a curve in a range of hills, or an arm of a prairie extending into, or partly surrounded by, a forest.  (b) A Carolina Bay.  GG & GSST.
(a) Commonly an extensive, low relief area of till, having an uneven or undulating surface, and commonly bounded on the distal end by a recessional or end moraine; (b) A layer of poorly sorted rock and mineral debris (till) dragged along, in, on, or beneath a glacier and deposited by processes including basal lodgment and release from downwasting stagnant ice by ablation.  Compare - end moraine, recessional, moraine, terminal moraine.
(a) One of a series of long, parallel, close fitting, crescent-shaped ridges and troughs formed along the inner bank of a stream meander as the channel migrated laterally down-valley and toward the outer bank.  Compare - meander belt, point bar.  (b) (not recommended; refer to oxbow lake) - A small, elongate lake on a flood plain in a well-defined part of an abandoned stream channel.  GG
(a) The main stream of an intermontane valley, flowing in the deepest part of the valley and parallel to its longest dimension.  (b) A stream that follows the axis of a syncline or anticline.  GG
(a) The shoreline, especially a former (relict) shoreline now elevated above the present water level, that commonly appears as a bench or line wrapping around the landscape at a common elevation.  SW  (b) A beach, especially one raised above the present sea or lake level.  GG
(colloquial  southeastern US)  Broad, low gradient (generally < 1 % slope but up to 2% near drainageways), low relief interstream areas characterized by non-hydric, poorly drained soils (seasonal saturation or water table) at depths of 15 to 45 cm (6 to 18 inches), and naturally forested by pines that dominate the Lower Coastal Plain of the southeastern US.  Regional differences occur in dominant vegetation and soil material (e.g. in south Florida, soils are dominantly sandy Spodosols and the understory is dominantly saw palmetto).  Hydropedologically and elevationally this landform occurs slightly above minor depressions (which have a seasonal water table at or above the surface), drainageways, and heads-of drains, but lies below better drained and slightly higher small rises or knolls.  Generally they are most extensive toward the interiors of low, broad interstream divides and away from drainageways.  SW
(colloquial  US Gulf Coast )  A series of low ridges and troughs on an essentially flat surface on barrier islands formed by dune field migration during alternating wet and dry periods; a type of interdune.  Troughs are eroded down to the wet sand level during drought periods (dune slack), while the ridges are stabilized by vegetation that invades the edge of dune fields during wet periods.  Compare  blowout, deflation basin.
(colloquial - Southern High Plains)  A linear or curvilinear ridge of windblown, granular material (generally sand or parna) removed from the adjacent basin by wind erosion (deflation), and deposited on the leeward (prevailing downwind) margin of a playa, playa basin, or salina basin.  The dune may be barren or vegetated.  Compare - dune.  SW
(colloquial - Southern High Plains)  The convex, upper margin (shoulder) of a playa basin where the playa slope intersects the surrounding terrain.  Compare - playa slope.  SW
(colloquial - Southern High Plains)  The generally concave to slightly convex area within a playa basin that lies between the relatively level playa floor below (or playa step, if present) and the convex playa rim above.  Overland flow is typically parallel down slope.  Compare - playa step, playa rim.  SW
(colloquial - Southern High Plains)  The lowest extensive, flat to slightly concave surface within a playa basin, consisting of a dry lake bed or lake plain underlain by stratified clay, silt or sand, and commonly by soluble salts.  Compare - playa step.  SW
(colloquial - Southern High Plains)  The relatively level or gently inclined "terrace-like" bench or toeslope within a large playa basin flanking and topographically higher than the playa floor and below the playa slope; a bench or step-like surface within a playa basin that breaks the continuity of the playa slope and modified by erosion and/or deposition.  Temporary ponding may occur in response to precipitation / runoff events.  Compare - playa slope.  SW
(colloquial - Southern High Plains) The generally concave to slightly convex area within a playa basin that lies between the relatively level playa floor below (or playa step, if present) and the convex playa rim above.  Overland flow is typically parallel down slope.  Compare - playa step, playa rim.  SW
(colloquial - Southern High Plains) The relatively level or gently inclined "terrace-like" bench or toeslope within a large playa basin flanking and topographically higher than the playa floor and below the playa slope; a bench or step-like surface within a playa basin that breaks the continuity of the playa slope and modified by erosion and/or deposition.  Temporary ponding may occur in response to precipitation / runoff events.  Compare - playa slope.  SW
(colloquial - western USA) The dominant gentle slope at the foot of a mountain; generally used in terms of intermontane-basin terrain in arid to subhumid regions.  Main components include: (a) An erosional surface on bedrock adjacent to the receding mountain front (pediment, rock pediment); (b) A constructional surface comprising individual alluvial fans and interfan valleys, also near the mountain front; and (c) A distal complex of coalescent fans (bajada), and alluvial slopes without fan form.  Piedmont slopes grade to basin-floor depressions with alluvial and temporary lake plains or to surfaces associated with through drainage (e.g., axial streams).  Compare - bolson, fan piedmont.  HP
(colloquial; southwestern USA)  The flood plain of an ephemeral stream that is confined between the fan remnants, ballenas, basin-floor remnants, or closely-opposed fan toeslopes of a basin.  FF & SW.
(colloquial:  western U.S.A.; not preferred - refer to ravine)  A small stream channel, narrow and steep-sided in cross section, and larger than a gully, cut in unconsolidated materials.  General synonym - ravine.  Compare - arroyo, draw, gully, wash. HP
(colloquial:  western U.S.A.)  A relatively flat, erosional remnant of any former landform of a basin floor that has been dissected following the incision of an axial stream.  FFP
(colloquial:  western USA) A landscape or large tract of steep, rough or broken land dissected by ravines and gullies and marks a sudden change in topography as from an elevated plain to lower hilly terrain, or a line of irregular cliffs at the edge of  a mesa or a river (e.g., the Missouri River breaks).  SW & GG
(colloquial: Caribbean Basin)  An isolated, steep-sided, commonly asymmetrical hill or ridge composed of limestone, generally steeper on its leeward side (prevailing downwind side) and surrounded by nearly level to sloping coastal plain composed of marine and alluvial sediments; a type of karst tower.  They range in height from a few feet (< 1 m) to over 150 ft (50 m).  Most are isolated and cover small areas but some form clusters of hills or ridges rising out of the surrounding blanket deposits.  Mogotes are extensive in northern Puerto Rico.  SW, Monroe ( 1976, 1980), & WW.
(colloquial: Gulf Coast U.S.A.)  Low, flattened, approximately circular or elliptical features composed of sandy loam that is coarser than, and distinct from, the surrounding soil; the basal diameter ranges from 3 m to more than 30 m, and the height from 30 cm to more than 2 m.  Compare -  mima mound, patterned ground, shrub-coppice dune.  GG
(colloquial: Hawaii) A natural surface channel commonly found near the middle of an a'a lava flow, formed by the surficial draining of molten lava rather than by erosion from running water; a type of lava trench.  Compare - lava tube.  MA
(colloquial: midwestern USA) Commonly an erosional remnant modified by depositional processes consisting of a low, elongated, rounded ridge or hill consisting mainly of drift, rock, or windblown sand, silt, or clay capped with a thick cover of loess; found especially in northeast Iowa.  Height varies between 10 and 30 m.  GG
(colloquial: northwest USA, and ND) A dry or intermittent stream valley or wash, especially a long, steep-walled gorge representing a Pleistocene overflow channel that carried meltwater from an ice sheet, e.g. the Grand Coulee in Washington State.  HP
(colloquial: southeastern U.S.A.)  A large wet area on broad, commonly a swamp, which occurs on nearly level interfluves in the Atlantic coastal plain with distinctive, native vegetation relative to adjacent areas.  Soils may be either mineral or organic.  A Native American term for "swamp on a hill."   Compare - raised bog.  RD
(colloquial: southeastern USA)  A type of very wide, low gradient (level to nearly level) interfluve that lacks a well developed drainage network such that large portions of the local upland lack stream channels or other drainageways; extensive in lower coastal plains and some lake plains, till plains and alluvial plain remnants.  Compare - interfluve.  SW & RD
(colloquial: southwestern U.S.A.) A broad, gently inclined alluvial piedmont slope extending from the base of a mountain range out into a basin and formed by the lateral coalescence of a series of alluvial fans.  Typically it has a broadly undulating transverse profile, parallel to the mountain front, resulting from the convexities of component fans.  The term is generally restricted to constructional slopes of intermontane basins.  Synonym - coalescent fan piedmont.  Compare - colluvial apron.  HP & SW
(colloquial: southwestern U.S.A.) A broad, gently inclined alluvial piedmont slope extending from the base of a mountain range out into a basin, and formed by the lateral coalescence of a series of alluvial fans.  Typically it has a broadly undulating transverse profile, parallel to the mountain front, resulting from the convexities of component fans.  The term is generally restricted to constructional slopes of intermontane basins.  Synonym - coalescent fan piedmont.  Compare - colluvial apron.  HP & SW
(colloquial: southwestern USA) A natural depression or cavity in impervious rocks in which water collects and remains for the greater part of the year.  GG
(colloquial: U.S. Virgin Islands, Caribbean Basin)  A gully, ravine, small valley, or narrow passage on land. GG
(colloquial: western U.S.A.)  A fan remnant having a distinctively-rounded surface of fan alluvium.  The ballena's broadly-rounded shoulders meet from either side to form a narrow summit and merge smoothly with concave side slopes and then concave, short pediments which form smoothly-rounded drainageways between adjacent ballenas.  A partial ballena is a fan remnant large enough to retain some relict fan surface on a remnant summit.  Compare - fan remnant.
(colloquial: western U.S.A.)  The broad, flat-flooded channel of an ephemeral stream, commonly with very steep to vertical banks cut in alluvium.  Note:  When channels reach intersect zones of ground-water discharge they are more properly classed as "intermittent stream" channels.  Synonym - arroyo.  Compare - gully.  HP
(colloquial: western U.S.A.) A rounded, dome-shaped hill, formed either by erosion or uplift.  GG
(colloquial: western U.S.A.) A wide, gently-sloping portion of a bolson floor comprising numerous, parallel, closely-spaced, relict longshore-bars and lagoons built by a receding pluvial lake.  Synonym, offshore barrier, offshore beach, bar beach.  Compare - bar [coast], barrier island.  GG and FFP
(colloquial: western USA.) A term applied to an internally drained (closed) intermontane basin in arid regions where drainages from adjacent mountains converge toward a central depression.  Bolsons are often tectonically formed depressions. According to Peterson, a bolson can include alluvial flat, alluvial plain, beach plain, barrier beach, lake plain, sand sheet, dune, and playa landforms.  The piedmont slope above a bolson includes erosional (pediments) and older depositional surfaces (fans) that adjoin the mountain front.  A semi-bolson is an externally drained (open) bolson.  Synonym - intermontane basin.  GG and FFP
(colloquial: western USA) A wide desert basin or valley that is drained by an intermittent stream, an externally drained (open) intermontane basin.  Compare - bolson  GG
(not preferred  use tidal flat)  A relatively level area of fine grained material (e.g. silt) along a shore (as in a sheltered estuary) or around an island, alternately covered and uncovered by the tide or covered by shallow water, and barren of vegetation.  Compare  low marsh, tidal flat, tidal marsh.  GG
(not preferred - see pyroclastic flow, pyroclastic surge)  A highly heated mixture of volcanic gases and ash, traveling down the flank of a volcano or along the surface of the ground; produced by the explosive disintegration of viscous lava in a volcanic crater, or by the explosive emission of gas-charged ash from a fissure or group of fissures.  The solid materials contained in a typical ash flow are generally unsorted and ordinarily include volcanic dust, pumice, scoria, and blocks in addition to ash.  (Also called a pyroclastic flow.)  Compare - nue ardente, lahar, pyroclastic.  GG
(not preferred - use karst).  A landscape dominated by dissolution features (e.g., sinkhole, blind valley, closed depressions, underground drainage) formed in soluable rocks.  SW & GG
(not preferred) refer to ballena  - (colloquial: western U.S.A.)  A fan remnant having a distinctively-rounded surface of fan alluvium.  The ballena's broadly-rounded shoulders meet from either side to form a narrow summit and merge smoothly with concave sideslopes and then concave, short pediments which form smoothly-rounded drainageways between adjacent ballenas.  A partial ballena is a fan remnant large enough to retain some relict fan surface on a remnant summit.  Compare - fan remnant.  Modified from FFP
(not preferred) refer to cirque headwall.
(not preferred) use rotational slide.
(not recommended - use meteorite crater)  A generally circular crater formed by the impact of an interplanetary body (projectile) on a planetary surface.  GG
(not recommended as a landform term - use avalanche chute).  The path formed by an avalanche.  It may take the form of an open path in a forest, with bent and broken trees, or an eroded surface marked by pits, scratches, and grooves.  Compare - avalanche chute  GG
(not recommended: obsolete) use shrub-coppice dune.
(not recommended) use disintegration moraine.
(not recommended) use hillslope.
(not recommended) use mountain slope.
(not recommended) use plug.
(refer to berm.)  A low, impermanent, nearly horizontal or landward-sloping shelf, ledge, or narrow terrace on the backshore of a beach, formed of material thrown up and deposited by storm waves; it is generally bounded on one side or the other by a beach ridge or beach scarp.  Some beaches have no berms, others have one or several.  GG
(refer to lake plain) (a) A imprecise term for a slight increase in slope and elevation of the land surface, usually with a broad summit and gently sloping sides.  GG (b) [soil survey] same as (a) but the term is restricted to microfeatures in areas of very low relief such as lake plains or coastal plains.  SW
[beach] A low, impermanent, nearly horizontal or landward-sloping shelf, ledge, or narrow terrace on the backshore of a beach, formed of material thrown up and deposited by storm waves; it is generally bounded on one side or the other by a beach ridge or beach scarp.  Some beaches have no berms, others have one or several.  GG
[coast] A shallow stretch of salt or brackish water, partly or completely separated from a sea or lake by an offshore reef, barrier island, sandbank or spit.  GG 87.   [relict landform]  A nearly level, filled trough or depression behind the longshore bar on a barrier beach and built by a receding pluvial or glacial lake.  Compare - sewage lagoon.   FFP
[coast] A shallow stretch of salt or brackish water, partly or completely separated from a sea or lake by an offshore reef, barrier island, sandbank or spit.  GG.  [relict landform] A nearly level, filled trough or depression behind the longshore bar on a barrier beach and built by a receding pluvial or glacial lake. Compare - sewage lagoon.
[geomorghology] (not preferred) A generic, imprecise term for any pot-shaped pit or hole.

[glacial geology] A term applied to a small pit depression (1 to 15 meters deep), generally circular or elliptical, occurring in an outwash plain, a recessional moraine, or a till plain.

[lake] - A shallow depression, generally less than 10 hectares in area, occurring on disintegration moraines and commonly containing an intermittent or seasonal pond or marsh.  GG
[geomorphology] - (a) (adjective)  Said of an area characterized by a continuous surface or stretch of land that is smooth, even, or horizontal, or nearly so, and that lacks any significant curvature, slope, elevations, or depressions.  (b) (noun)  An informal, generic term for a level or nearly level surface or small area of land marked by little or no local relief.  Compare - mud flat.  (c) (not recommended) A nearly level region that visibly displays less relief than its surroundings.  GG.

[lake] (not recommended)  (a) The low-lying, exposed, flat land of a lake delta or of a lake bottom. Compare - lake plain.  (b) The flat bottom of a desiccated lake in the arid parts of western USA.  Compare - playa, pluvial lake.
[structural geology] A curve or bend of a planar structure such as rock strata, bedding planes, foliation, or cleavage.  GG
A bank or slope portion of a cut excavated into unconsolidated material (regolith) or bedrock as in a roadcut, whose slope gradient has been mechanically reduced to a subdued angle (e.g. to < 33 %) to increase slope stability, reduce erosion, or to facilitate revegetation.  Compare - cut, cutbank, roadcut.  SW
A basin-like, rimmed structure, usually at the summit of a volcanic cone.  It may be formed by collapse, by an explosive eruption or by the gradual accumulation of pyroclastic material into a surrounding rim.  Compare - caldera.   GG
A bizzarrely shaped column, pinnacle, or pillar of rock produced by differential weathering or erosion in a region of sporadically heavy rainfall.  Formation is facilitated by joints and layers of varying hardness.  Compare - earth pillar.  GG
A bluff composed of a thick deposit of coarse loess, formed immediately adjacent to the edges of flood plains, as along the Mississippi River valley or China.  Sometimes referred to as a bluff formation (not preferred).  Modified substantially from GG.
A body of alluvium, nearly flat and fan-shaped, deposited at or near the mouth of a river or stream where it enters a body of relatively quiet water, usually a sea or lake.  HP
A bog that is at or only slightly above the water table, on which it depends for accumulation and preservation of peat (chiefly the remains of sedges, reeds, shrubs, and various mosses).  Compare - highmoor bog, raised bog.  GG
A bog, often on the uplands, whose surface is covered by sphagnum mosses which, because of their high degree of water retention, make the bog more dependent upon precipitation than on the water table.  The bog often occurs as a raised peat bog or blanket bog.  Compare - lowmoor bog, raised bog.  GG
A bog, usually a sphagnum bog, frequently with grassy tussocks (hummocks), growing in wet, poorly drained boreal regions, with deep accumulations of organic material, often in areas of permafrost; a moss-covered muck or peat bog of boreal regions.  GG  and HP
A breccia-filled volcanic pipe that was formed by a gaseous explosion (e.g. hydrovolcanic eruption); commonly, but not exclusively associated with exposed throat or neck of maar, as in the Hopi Buttes area of Arizona.  Compare - neck [volcanic].
A broad area of nearly level land, that can be localized but is commonly hundreds of square kilometers in extent, covered by a relatively thin succession of primarily basaltic lava flows resulting from fissure eruptions.  Compare - lava plateau, lava field, volcanic field.  SW & GG
A broad deposit of nonsorted, water-saturated, locally derived material that is moving or has moved downslope, en masse.  Stripes are commonly associated with solifluction sheets.  Compare - stripe. NRC
A broad elevated tableland or flat-topped highland, that may be localized but commonly is many hundreds or thousands of square kilometers in extent, underlain by a thick succession of basaltic lava flows resulting from fissure eruptions (e.g. Columbia River Plateau).  Compare - lava plain, lava field.  GG
A broad, low lying, nearly level sand flat that is alternately inundated by ponded rainwater or by wind-driven bay or estuarine water from storm surges or seiche.  Frequent salinity fluctuations and prolonged periods of exposure preclude establishment of most types of vegetation except for mats of filamentous blue-green algae.  Compare  tidal flat.  (modified from Fisk, 1959)
A broad, nearly flat-topped, and usually isolated landmass bounded by steep slopes or precipitous cliff and capped by layers of resistant, nearly horizontal, rocky summit width greater than the height of bounding escarpments.  (Colloquial: western USA; not preferred)  Also used to designate broad structural benches and alluvial terraces that occupy intermediate levels in stepped sequences of platforms bordering canyons and valleys.  Compare - butte, plateau, cuesta.  HP & GG
A broad, nearly horizontal intertidal surface formed across carbonate rocks, produced primarily by solution with contributions by intertidal weathering and biological erosion and deposition, not by abrasion.  Compare  wave-cut platform.  SW & GG
A category of mass movement processes, associated sediments (complex landslide deposit) or resultant landforms characterized by a composite of several mass movement processes none of which dominates or leaves a prevailing landform.  Numerous types of complex landslides can be specified by naming the constituent processes evident (e.g. a complex earth spread - earth flow landslide).  Compare - fall, topple, slide, lateral spread, flow, landslide.  SW &  DV
A category of mass movement processes, associated sediments (flow deposit) and landforms characterized by slow to very rapid downslope movement of unconsolidated material which, whether saturated or comparatively dry, behaves much as a viscous fluid as it moves. Types of flows can be specified based on the dominant particle size of sediments (i.e. debris flow (e.g., lahar), earth flow (creep, mudflow), rock fragment flow (e.g., rockfall avalanche), debris avalanche]. Compare - fall, topple, slide, lateral spread, complex landslide, landslide.  SW & DV
A category of mass movement processes, associated sediments (lateral spread deposit) or resultant landforms characterized by a very rapid spread dominated by lateral movement in a soil or fractured rock mass resulting from liquefaction or plastic flow of underlying materials; also called spread.  Types of lateral spreads can be specified based on the dominant particle size of sediments (i.e. debris spread, earth spread, rock spread.  Compare - fall, topple, slide, flow, complex landslide,landslide.  SW, DV & GG
A category of mass movement processes, associated sediments (translational slide deposit) or resultant landforms characterized by the extremely slow to moderately rapid downslope displacement of comparatively dry soil-rock material on a surface (slip face) that is roughly parallel to the general ground surface, in contrast to falls topples, and rotational slides.  The term includes such diverse slide types as translational debris slides, translational earth slide, translational rock slide, block glides, and slab or flake slides. .  Compare - rotational slide, slide, landslide.  SW, DV, GG
A category of processes, associated sediments (topple deposit) or resultant landforms characterized by a localized, very rapid type of fall in which large blocks of soil or rock literally fall over, rotating outward over a low pivot point.  Portions of the original material may remain intact, although reoriented, within the resulting debris pile. Types of topples can be specified based on the dominant particle size of sediments (i.e. debris topple, soil topple, rock topple.  Compare - fall, flow, slide, spread, complex landslide, landslide.  SW & DV
A channel formed by an ice-marginal, englacial, or subglacial stream during glaciation.  GG
A channel or stream with multiple channels that interweave as a result of repeated bifurcation and convergence of flow around inter-channel bars, resembling (in plan view) the strands of a complex braid.  Braiding is generally confined to broad, shallow streams of low sinuosity, high bed load, non-cohesive bank material, and a steep gradient.  At a given bank-full discharge, braided streams have steeper slopes and shallower, broader, and less stable channel cross sections than meandering streams.  Compare - meandering channel, flood-plain landforms.  HP
A channel remnant of a former tidal inlet. The channel was cutoff or abandoned by infilling from migrating shore sediments.  Compare  inlet, tidal inlet.
A cliff or slope produced by wave erosion, situated at the seaward edge of the coast or the landward side of the wave-cut platform.  It may vary from an inconspicuous slope to a high, steep escarpment.  GG
A closed depression formed by the coalescence of multiple sinkholes; an elongate, solutional valley.  Its drainage is subsurface, diameters range from several hundred meters to a few kilometers, and it usually has a scalloped margin inherited from the sinkholes.  It may have nominal, local channel flow (small streams), sequential sinkhole inlets (springs) and outlets (swallow hole, etc.); also called compound sinkhole (not preferred), uvala (not preferred).  Compare - sinkhole, interior valley.  SW & GG
A closed depression or doline into which all or part of a stream disappears underground.  GG
A closed, circular or elliptical depression, commonly funnel-shaped, characterized by subsurface drainage and formed either by dissolution of the surface of underlying bedrock (e.g., limestone, gypsum, salt) (solution sinkhole) or by collapse of underlying caves within bedrock (collapse sinkhole); diameters range from a few meters to as much as 1000 m.  Complexes of sinkholes in carbonate-rock terrain are the main components of karst topography.  Synonym (not preferred) - doline.  Compare - karst valley, interior valley, cockpit.  SW & WW
A closely looping stream meander having an extreme curvature such that only a neck of land is left between the two parts of the stream.  (colloquial: northeastern U.S.A.) the land enclosed, or partly enclosed, within an oxbow.  Compare - meander belt, oxbow lake, bayou.  GG
A coastal dune or dune ridge oriented parallel to the shoreline, occurring at the landward margin of the beach, along the shoreward face of a beach ridge, or at the landward limit of the highest tide, and more or less stabilized by vegetation.  GG
A comparatively flat area of great extent and elevation; specifically an extensive land region considerably elevated (more than 100 meters) above adjacent lower-lying terrain, and is commonly limited on at least one side by an abrupt descent, has a flat or nearly level surface.  A comparatively large part of a plateau surface is near summit level.  Compare - hill, foothill, mountain, mesa, plain.  GG
A comparatively level area, usually with road access, constructed or cut into steeper slopes and used for sorting logs during timber harvest operations.  Compare - skid trail.  SW
A conical hill formed by the accumulation of cinders and other pyroclastics, normally basaltic or andisitic composition.  Slopes generally exceed 20 percent.  GG
A conical hill of lava and/or pyroclastics that is built up around a volcanic vent.  GG
A conically-shaped residual hill in karst with a rounded top and relatively steep, convex (e.g. parabolic) side slopes, commonly in tropical climates.  Compare - karst tower, mogote.  SW & WW
A constructional coastal strip, sloping gently seaward and/or down valley, veneered by or completely composed of unconsolidated fluviomarine deposits (typically silt, sand, fine gravel).  Compare  terrace, stream terrace, marine terrace.  SW
A constructional coastal strip, sloping gently seaward and/or down valley, veneered by or completely composed of unconsolidated sediments (typically silt, sand, fine gravel).  Sediments were deposited by both marine and fluvial processes, resulting from sea level flucuations and/or stream migration (e.g. materials deposited in a nearshore environment and reworked by fluvial processes as sea level fell, or visa versa as sea level rose).  Compare - terrace, stream terrace, marine terrace.
A constructional coastal strip, sloping gently seaward, veneered by marine deposits (typically silt, sand, fine gravel).  Compare - terrace, wave-built terrace.  GG
A continuous and level or undulating area formed by closely spaced successive embankments of wave-deposited beach material added more or less uniformly to a prograding shoreline, such as to a growing compound spit or to a cuspate foreland.  Compare - wave-built terrace, cheneir plain.  GG
A coral reef appearing in plan view as roughly circular, and surmounted by a chain of closely spaced, low coral islets that encircle or nearly encircle a shallow lagoon in which there is no land or islands of non-coral origin; the reef is surrounded by open sea.  GG
A crescent-shaped dune with tips extending leeward (downwind), making this side concave and the windward (upwind) side convex.  Barchan dunes tend to be arranged in chains extending in the dominant wind direction.  Compare - parabolic dune.  HP
A crudely star-shaped, closed depression (i.e. large sinkhole) in tropical karst having an inverted conical or slightly concave floor, with an irregular or serrate  perimeter formed by subsidiary solution channels and corridors into adjacent hills, and surrounded by residual hills with steep, concave side slopes; the dominant type of closed depression in cockpit karst.  Compare - sinkhole, kegel karst.  SW, WW & GG
A damp depression or trough between dunes in a dune field or dune ridges on a shore, caused by intersecting the capillary fringe of the local water table; a moist type of interdune.  Compare - interdune, dune lake.  SW & GG
A deeply and extensively dissected landscape composed predominantly of relatively narrow, steep-walled valleys with small flood plains or valley floors; commonly with considerable outcrops of hard bedrock on steep slopes, ledges, or cliffs, and with broader summits or interfluves than found in badlands.  Side slopes exhibit extensive erosion, active back-wearing, and relatively sparse vegetation.  SW
A depression, ditch or pit excavated to furnish gravel for roads or other construction projects; a type of borrow pit.  SW
A depression, ditch or pit excavated to furnish sand for roads or other construction projects off-site; a type of borrow pit.  SW
A depression, open to the sky, resulting from the surface extraction of earthy material (e.g. soil / fill) or bedrock material (e.g. coal).  Compare - borrow pit, openpit mine, quarry.  SW
A displaced crustal unit, formed during block faulting, that is bounded by faults, either completely or in part, and behaves as a coherent unit during tectonic activity.
A dissolution groove or trench formed along vertical bedrock fractures beneath soil and usually buried beneath regolith with little or no ground surface expression, commonly wider than a solution fissure (widths commonly range from 0.5 to 3 meters) and tapering down to a crack or a bedrock floored trench; also called grike (not preferred), or subsurface karren.  Compare - karren, solution fissure, solution corridor.
A dissolution groove or trench formed along vertical bedrock fractures beneath soil and usually buried beneath regolith with little or no ground surface expression, commonly wider than a solution fissure (widths commonly range from 0.5 to 3 meters) and tapering down to a crack or a bedrock floored trench; also called grike (not preferred), subsurface karren (not preferred).  Compare - karren, solution fissure, solution corridor.  SW & WW
A dome or anticlinal fold in which the overlying rocks or sediments have been ruptured by the squeezing-out of plastic core material.  Diapirs in sedimentary strata usually contain cores of salt or shale; igneous intrusions may also show diapiric structure.  GG
A drift topography characterized by chaotic mounds and pits, generally randomly oriented, developed in supraglacial drift by collapse and flow as the underlying stagnant ice melted.  Slopes may be steep and unstable and there will be used and unused stream courses and lake depressions interspersed with the morainic ridges.  Characteristically, there are numerous abrupt, lateral and vertical changes between unconsolidated materials of differing lithology.  SJ & SW
A dune formed by the piling-up of sand by wind against a cliff or mountain slope; very common in arid regions with substantial local relief and strong prevailing winds.  Compare - sand ramp.  GG & SW
A dune largely composed of silt and sand-sized aggregates of clay; sometimes called a clay dune or lunette.    Compare - parna.  HP
A fan-like of sand washed over a barrier island or spit during a storm and deposited on the landward side.  Washover fans can be small to medium sized and completely subaerial, or they can be quite large and include subaqueous margins extending into adjacent lagoons or estuaries.  Large fans can be subdivided into sequential parts: ephemeral washover channel (microfeature) cut through dunes or beach ridges, back-barrier flats, (subaqueous) washover-fan flat, (subaqueous) washover-fan slope.  Subaerial portions can range from barren to completely vegetated.
A fan-shaped accumulation of outwash deposited by meltwater streams in front of the end moraine of a glacier.  Coalescing outwash fans form an outwash plain.  GG
A fan-shaped deposit or other outspread deposit formed where an overloaded stream breaks through a levee (natural or artificial) and deposits its material (often coarse-grained) on the flood plain.  Compare - crevasse.  GG
A fast density current of pyroclastic material, usually very hot, composed of a mixture of gasses and a variety of pyroclastic particles (ash, pumice, scoria, lava fragments, etc.); produced by the explosive disintegration of viscous lava in a volcanic crater or by the explosive emission of gas-charged ash from a fissure and which tends to follow topographic lows (e.g. valleys) as it moves; used in a more general sense than ash flow.  Compare - pyroclastic surge, ash flow, nue ardente, lahar.  SW, SN, GG
A fault that is expressed as a zone of numerous small fractures or of breccia or fault gouge.  A fault zone may be as wide as hundreds of meters.  Compare - fault, fault-scarp.  GG
A flat-topped bank of outwash with an abrupt outer face (scarp or riser) extending along a valley downstream from an outwash plain or terminal moraine; a valley train deposit.    Compare - kame terrace, valley train.  GG
A flood-plain landform.  Extensive, marshy, or swampy, depressed areas of flood plains between natural levees and valley sides or terraces.  Compare - valley flat.  HP
A flow of wet sand, as along banks of noncohesive clean sand that is subject to scour and to repeated fluctuations in pore-water pressure due to rise and fall of the tide.  GG
A form of patterned ground whose horizontal mesh is dominantly circular.  Compare - Nonsorted circle, patterned ground.  GG
A general name used to describe several types of humid tropical karst landscapes characterized by numerous, closely spaced cone- (cone karst), hemispherical- (halbkugelkarst), or tower-shaped (tower karst) hills with vertical or near-vertical walls and having intervening closed depressions and narrow steep-walled karst valleys or passageways.  Compare - cockpit karst.  GG & SW
A general term for a broad upland mass with nearly level or undulating summit area of large extent and steep side slopes descending to surrounding lowlands.  Compare - plateau, mesa, cuesta.  HP
A general term for a landform composed mainly of till that has been deposited by a glacier; a kame moraine is a type of  moraine similar in exterior form to other types of moraines but composed mainly of stratified outwash materials.  Types of moraine include: disintegration, end, ground, kame, lateral, recessional, and terminal.  SW
A general term for a ridge-like accumulation of sand, gravel, or other alluvial material formed in the channel, along the banks, or at the mouth of a stream where a decrease in velocity induces deposition; e.g. a channel bar or a meander bar.  [coast] - A generic term for any of various elongate offshore ridges, banks, or mounds of sand, gravel, or other unconsolidated material submerged at least at high tide, and built up by the action of waves or currents, especially at the mouth of a river or estuary, or at a slight distance offshore from the beach.  Compare - longshore bar.  GG & GSST
A general term for a series of rock strata that dip in one direction with a uniform angle; e.g. one limb of a fold, a tilted fault block, or an isocline.  Compare - cuesta, homoclinal ridge, hogback.
A general term for any ground surface exhibiting a discernibly ordered, more-or-less symmetrical, morphological pattern of ground and, where present, vegetation.  Patterned ground is characteristic of, but not confined to, permafrost regions or areas subjected to intense frost action; it also occurs in tropical, subtropical, and temperate areas.  Patterned ground is classified by type of pattern and presence or absence of sorting and includes nonsorted and sorted circles, net, polygons, steps and stripes, garlands, and solifluction features.  In permafrost regions, the most common macroform is the ice-wedge polygon and a common microform is the nonsorted circle.  Stone polygons generally form on slopes of less than 8 percent, while garlands and stripes occur on slopes of 8 to 15 percent and more than 15 percent, respectively.  NRC and HP
A general term for landforms that are the remaining parts of older fan-landforms, such as alluvial fans, fan aprons, inset fans, and fan skirts, that either have been dissected (erosional fan-remnants) or partially buried (nonburied fan-remnants).  An erosional fan remnant must have a relatively flat summit that is a relict fan-surface.  A nonburied fan-remnant is a relict surface in its entirety.  Compare - eroded fan remnant, ballena.  FFP.
A general term for the nearly level to gently sloping, lowest surface of a valley.  Landforms include axial stream channels, the flood plain, flood-plain steps, and, in some areas, low terrace surfaces.  Compare - flood-plain landforms, meander, braided channel, valley side.  HP
A general term for the nearly level, lower-most part of intermontane basins (i.e. bolsons, semi-bolsons).  The floor includes all of the alluvial, eolian, and erosional landforms below the piedmont slope.  Compare - basin, piedmont slope.
A general term for the nearly level, lower-most part of intermontane basins (i.e. bolsons, semi-bolsons).  The floor includes all of the alluvial, eolian, and erosional landforms below the piedmont slope.  Compare - basin, piedmont slope.  FFP
A general term referring to any flat, lowland area, large or small, at a low elevation.  Specifically, any extensive region of comparatively smooth and level gently undulating land.  A plain has few or no prominent hills or valleys but sometimes has considerable slope, and usually occurs at low elevation relative to surrounding areas.  Where dissected, remnants of a plain can form the local uplands.  A plain may be forested or bare of trees and may be formed by deposition or erosion.  Compare - lowland, plateau.  GG
A general, encompassing term for most types of mass movement landforms and processes involving the downslope transport and outward deposition of soil and rock materials, caused by gravitational forces and which may or may not involve saturated materials.  Names of landslide types generally reflect the dominant process and/or the resultant landform.  The main operational categories of mass movement are fall (rockfall, soil fall, topple), slide (rotational landslide, block glide, debris slide, lateral spread), flow [rock fragment flow, (especially rockfall avalanche), debris avalanche, debris flow (e.g., lahar), earthflow (creep, mudflow)], and complex landslides.  Compare - solifluction.  SW & DV
A generally circular or elliptical depression formed by hypervelocity impact of an experimental projectile or ordinance into earthy or rock material.  Compare - caldera, crater, meteorite crater.  SW
A generally flat-topped expanse of peat, elevated above the general surface of a peatland, and containing segregated ice that may or may not extend downward into the underlying mineral soil.  Controversy exists as to whether peat plateaus and palsen are morphological variations of the same feature.  NRC
A generic name for a small, low hill, generally between 3 - 30 m in height and slopes between 5 and 50% (e.g., bigger than a mound but smaller than a hill); commonly considered a microfeature.  Compare - mound, hill.  SW
A generic name for an elevated, generally rounded land surface with high local relief, rising between 90 meters (approx. 300 ft.) to as much as 300 m (approx. 1000 ft.) above surrounding lowlands.  Compare - low hill, hill, hillock.  SW
A generic name for an elevated, generally rounded land surface with low local relief, rising between 30 meters (100 ft.) to as much as 90 m (approx. 300 ft.) above surrounding lowlands.  Compare - high hill, hill, hillock.  SW
A generic name for any enclosed area that has no surface drainage outlet and from which water escapes only by evaporation or subsurface drainage; an area of lower ground indicated on a topographic map by a hachured contour line forming a closed loop.  Compare - open basin.  SW & GG
A generic name for any enclosed or low area that has a surface drainage outlet whereby surface water can leave the enclosure; an area of lower ground indicated on a topographic map by contour lines forming an incomplete loop or basin indicating at least one surface exit.  Compare - closed basin.  SW
A generic term for an elevated area of the land surface, rising at least 30 m (100 ft.) to as much as 300 meters (approx. 1000 ft.) above surrounding lowlands, usually with a nominal summit area relative to bounding slopes, a well-defined, rounded outline and slopes that generally exceed 15 percent.  A hill can occur as a single, isolated mass or in a group.  A hill can be further specified based on the magnitude of local relief: low hill (30 - 90 m) or high hill (90 - 300 m).  Informal distinctions between a hill and a mountain are often arbitrary and dependent on local convention. Compare - hillock, plateau, mountain, foothills, hills.  SW &  HP
A generic term for an elevated area of the land surface, rising more than 300 meters above surrounding lowlands, usually with a nominal summit area relative to bounding slopes and generally with steep sides (greater than 25 percent slope) with or without considerable bare-rock exposed.  A mountain can occur as a single, isolated mass or in a group forming a chain or range.  Mountains are primarily formed by tectonic activity and/or volcanic action and secondarily by differential erosion.  Compare - hill, hillock, plateau, foothills, mountains. SW & HP
A generic term for the low or relatively level ground lying between valley walls and bordering a stream channel; especially the small plain at the bottom of a narrow, steep-sided valley.  The term can be generally applied noncommittally to a flat surface that cannot be identified with certainty as a floodplain or terrace.  Compare - backswamp, meander belt.  GG
A generic term for the steeper part of a hill between its summit and the drainage line, valley flat, or depression floor at the base of the hill.  Compare - mountain slope. HP
A generic term for wide structural depressions between mountain ranges that are partly filled with alluvium and called "valleys" in the vernacular.  Intermontane basins may be drained internally (bolsons) or externally (semi-bolson).  FFP
A gently sloping coastal feature at the seaward or lakeward edge of a wave-cut platform, constructed by sediment brought by rivers or drifted along the shore or across the platform and deposited in the deeper water beyond.  Compare - submerged wave-built terrace, beach plain, strand plain.  GG
A gently sloping erosional surface developed at the foot of a receding hill or mountain slope, commonly with a slightly concave-upward profile, that cross-cuts rock or sediment strata that extend beneath adjacent uplands.  The erosion surface may be essentially bare bedrock (i.e. rock pediment), or it may be thinly mantled (e.g. 1 to 3 m) with debris such as colluvium, pedisediment, or alluvium (i.e. pediment) that is ultimately in transit from an upland front to basin or valley lowland.  In hill-footslope terrain the debris mantle (over an erosional contact) is designated "pedisediment."  The term has been used in several geomorphic contexts:  Pediments may be classed with respect to (a) landscape positions (e.g. intermontane-basin piedmont = apron pediment, or valley-border footslope surfaces (, =  terrace pediment); (Cooke and Warren, 1973); (b) type of material eroded (e.g. bedrock = rock pediment, or regolith = pediment); or (c) combinations of the above.  Compare - rock pediment, Piedmont slope, structural bench.
A gently sloping surface produced by wave erosion, extending into the sea or lake from the base of the wave-cut cliff.  This feature represents both the wave-cut bench and the abrasion platform (Jackson, 1997).  Compare - submerged wave-cut platform.  GG
A gently sloping, fan-like, subaqueous landform created by overwash from storm surges that transports sediment from the seaward side to the landward side of a barrier island (GG).  Sediment is carried through temporary overwash channels that cut through the dune complex on the barrier spit (Fisher and Simpson, 1979; Boothroyd et al., 1985; Davis, 1994) and spill out onto the lagoon-side platform where they coalesce to form a broad belt.  Also called storm-surge platform flat (Boothroyd et al., 1979) and washover fan apron (GG).  Compare  washover fan slope.
A glacial lake occupying a portion of a tunnel valley.  GG
A glaciated land area that has the characteristics of a till plain, but that was also inundated by a glacial lake. The area possesses a gently undulating till-topography rather than a distinctive, low-relief lake plain surface.  Lacustrine sediments, however, are absent or occur only sparsely, but a wave/current-modified, surficial mantle may commonly exist atop the till.  Topographic highs, which were once islands, may possess shore features (e.g., wave-cut scarps, strandlines, beach deposits).  Compare till-floored lake plain.
A glacier of considerable thickness completely covering a large part of a continent or an area of at least 50,000 square km, obscuring the underlying surface, such as the ice sheets covering Antarctica or Greenland.  Continental glaciers occupied northern portions of  the coterminous USA and Alaska in the past (e.g., Pleistocene) and usage commonly implies former continental glacier conditions.   Compare - alpine glacier.  SW & GG
A group of mountain ranges exhibiting certain unifying features, such as similarity in form, structure and alignment, and presumably originating from the same general causes; especially a series of mountain ranges belonging to an orogenic belt.  Compare - mountain range, mountains.  GG
A high, isolated pinnacle, or rocky peak; or a pile of rocks, much-jointed and usually granitic, exposed to intense weathering, and often assuming peculiar or fantastic shapes.  GG
A high, narrow, sharp-edged pass or saddle through a divide or between two adjacent peaks in a mountain range; especially a deep pass formed by the headward erosion and intersection of two cirques.  Compare - gap, pass, saddle.  GG
A high, rocky, sharp pointed, steep-sided, mountain peak with prominent faces and ridges, bounded by the intersecting walls of three or more cirques that have been cut back into the mountain by headward erosion of glaciers.  GG
A hill composed of thick deposits of loess, as in IA, MO, NE and the Palouse Hills of WA & ID.
A hill or ridge composed  of a lava flow remnant that caps or is exposed in a tilted fault block and bounded by a dip slope.  Used as evidence of block faulting in Basin-and-Range terrain (western USA).  Compare - hogback.  GG
A hollow in the ground resulting from subsidence following the local melting of ground ice in a permafrost region.  GG
A hummock consisting of vegetation and organic matter with or without a core of mineral soil or stones.  Compare - earth hummock, non-sorted circle, patterned ground.  NRC
A karst landscape dominated by both 1) karst features (deranged and subsurface drainage, blind valleys, swallow holes, large springs, closed depressions, and caves), generally limited to low-lying interfluve areas, and 2) surface drainage by large rivers, with associated fluvial features (adjacent stream terraces) and sediments (alluvium), that commonly maintain their surface courses and are fed by underground tributaries; the dominant karst in the eastern USA.  Compare - sinkhole karst, pavement karst, glaciokarst, karst.
A karst landscape dominated by subsurface drainage and serrate or star-shaped depressions (cockpits) that range widely in size and density but typically are considerably larger than sinkholes (dolines), and are separated by intermediate residual hills with concave side slopes; a common type of tropical karst (e.g. Jamaica).  Compare - kegel karst, karst.  SW & WW
A kind of topography formed in limestone, gypsum, or other soluble rocks by dissolution, and that is characterized by closed depressions, sinkholes, caves, and underground drainage.  Various types of karst can be recognized depending upon the dominant surface features:  karst dominated by closed depressions (sinkhole karst - temperate climates; cockpit karst - humid tropical climates), closed depressions and large rivers (fluviokarst), bare rock dominated by dissolution joints (pavement karst), tropical cone-, tower- or domed-hills (kegel karst), karst thinly mantled with glacial drift (glaciokarst), etc.
A lake formed in a period of exceptionally heavy rainfall; a lake formed in the Pleistocene Epoch during a time of glacial advance, and now either extinct (relict) or existing as a remnant (lake); e.g., Lake Bonneville.  Compare - glacial lake, proglacial lake.  GG
A lake plain formed on, and bounded by, glacial ice and subsequently "let down" or collapsed by the melting of underlying ice resulting in contortion or folding of the sediments and sedimentary structures.  Lacustrine sediments cap present topography.    Compare - lake plain.  SW & CF
A lakebed formed in a lake on glacial ice and subsequently "let down" or collapsed by the melting of underlying ice, resulting in contortion or folding or the lacustrine sediment and sedimentary structures.  These modified or distorted lacustrine sediments cap present-day topographic highs and generally lie at elevations higher than the surrounding disintegration moraine.  Compare - collapsed lake plain, collapsed ice-walled lakebed.  SW & CF
A lakebed that formed in a lake bounded by stagnant ice, but floored by solid ground, usually till.  Collapse features are limited to the lakebed margins.  Presently, these materials and sedimentary structures generally occur as roughly circular-shaped hills of till capped by lacustrine sediments, generally at elevations higher than surrounding disintegration moraine.  Compare - collapsed ice-floored lakebed, collapsed lake plain.  SW & CF
A land area covered by a relatively thick or distinctive, surficial deposit of volcanic ash (air fall) that can be traced to a specific source and has well defined boundaries.  An ash field can be distinguished from adjacent landforms or land areas based on ash thickness, mineral composition, and physical characteristics. Soils within an ash field form solely or predominantly within the ash deposit.
A land area where municipal solid waste is buried in a manner engineered to minimize environmental degradation.  Commonly the waste is compacted and ultimately covered with soil or other earthy material.  Compare - dump.  GG
A land area, usually a field, that has been mechanically flattened or smoothed to facilitate management practices such as flood irrigation; as a result the natural soil has been partially or completely modified (e.g., truncated or buried).  SW
A landform composed of the relatively undissected upland or ridge between two adjacent valleys containing streams flowing in the same general direction.  An elevated area between two drainageways that sheds water to those drainageways.  Compare - divide.  GG & FFP
A landform comprised of a thin, short, relatively young mantle of alluvium along the very upper margin  (near the proximal end or apex) of a major alluvial fan.   The young mantle somewhere buries an older soil that can be traced to the edge of the collar where the older soil emerges at the land surface as a relict soil.  Compare - fan apron.  FFP
A landform consisting of very low gradient, broad, barren, axial-stream channel segments in an intermontane basin.  It floods broadly and shallowly and is veneered with barren fine-textured sediment that crusts.  Commonly, a flood-plain playa is segmented by transverse, narrow bands of vegetation, and it may alternate with ordinary narrow or braided channel segments.  FFP
A landform produced in a region of limestone or sandstone by infrequent rains combined with wind action, and characterized by "a surface bristling with a fine lacework of sharp ridges pitted by corrosion".  GG
A landform that is a smoothly rounded rock mass such as a rock-capped mountain summit that roughly resembles a building dome.  (e.g. the rounded granite peaks of Yosemite, CA).  GG
A landform with a concave to planar surface composed of a thick wedge-shaped deposit of colluvium and/or slope alluvium  that forms the base (footslope) of a bluff, escarpment or steep slope .    Compare  beveled base.  SW
A landscape dominated by hills.  SW
A landscape dominated by subsurface drainage and sinkholes (dolines) that range widely in sizes and density; the most common type of karst in upland areas of temperate regions (e.g. Highland Rim of TN, northern FL, southwestern MO, etc.); also called doline karst (not preferred).  Compare - fluviokarst, pavement karst, glaciokarst, karst.
A landscape which is intricately dissected and characterized by a very fine drainage network with high drainage densities and short, steep slopes with narrow interfluves.  Badlands develop on surfaces with little or no vegetative cover, overlying unconsolidated or poorly cemented materials (clays, silts, or in some cases sandstones) sometimes with soluble minerals such as gypsum or halite.  GG
A large expanse of marshy land, covered mostly by grasses, e.g. the Florida Everglades.
A large frost mound; especially a relatively large conical mound of soil-covered ice (commonly 30 to 50 meters high and up to 400 meters in diameter) raised in part by hydrostatic pressure within and below the permafrost of Arctic regions, and of more than 1 year's duration.  GG
A large or small body of salt water in a marsh or swamp along the seacoast.  GG
A large, flat-floored closed depression in a karst area whose drainage is ultimately subsurface and its floor is commonly covered by alluvium.  Some interior valleys may become ephemeral lakes during periods of heavy rainfall, when sinking streams that drain them cannot manage the runoff; also called polje (not preferred).  Compare - karst valley, sinkhole.  GG
A large, generally discordant plutonic rock body exposed at the land surface, with an aerial extent > 40 sq. mi. (100 km2) and no known bottom (e.g. Idaho batholith).  Compare - stock.  SW & GG
A large, irregularly shaped, commonly thin, surficial mantle of eolian sand, lacking the discernible slip faces that are common on dunes.  GG
A large, isolated sand dune whose base, in plan view, resembles a star, with sharp-crested ridges converging from basal points to a central peak that may be as high as 100 m above the surrounding plain.  It tends to remain fixed for centuries in an area where the wind blows from all directions.  Compare - dune.  GG
A large, more or less circular depression, formed by explosion and/or collapse, which surrounds a volcanic vent or vents, and whose diameter is many times greater than that of the included vent, or vents.  Compare - crater.  GG
A large, sharp-crested, elongated, longitudinal (linear) dune or chain of sand dunes, oriented parallel, rather than transverse (perpendicular), to the prevailing wind.  If unmodified, the crest, in profile, commonly consists of a succession of curved slip faces produced by strong, but infrequent cross winds.  A seif dune may be as much as 200 m high and from 400 m to more than 100 km long.  Compare - longitudinal dune. GG and HP
A largely subaqueous (sometimes intertidal), crudely fan-shaped deposit of sand-sized sediment formed on the landward side of a tidal inlet (modified from Boothroyd et al., 1985; Davis, 1994; Ritter et al., 1995).  Flood tides transport sediment through the tidal inlet and into the lagoon over a flood ramp where currents slow and dissipate (Davis, 1994).  Generally, flood-tidal deltas along microtidal coasts are multi-lobate and unaffected by ebbing currents (modified from Davis, 1994).  Compare  flood-tidal delta slope.
A lava flow dominated by block lava.  Compare - `a`a lava flow, pahoehoe lava, pillow lava.  SW
A lava flow or body displaying pillow structure and considered to have formed in a subaqueous environment (underwater); usually basaltic or andesitic in composition.  Compare - `a`a lava flow, block lava flow, pahoehoe lava flow.
A linear depression formed by a drainageway that is incised considerably below the surface of an alluvial fan.  GG
A linear or arcuate opening left in the soil after a plow or disk has opened a shallow channel at the soil surface.  A shallow channel cut in the soil surface, usually between planted rows for controlling surface water and soil loss, or for conveying irrigation water. GSST
A lineation or streamlined groove and ridge parallel to the direction of ice movement, formed in newly deposited till or older drift.  They range in height from a few centimeters to 25 m, and in length from a few meters to 20 km.  GG
A lineation or streamlined groove or ridge parallel to the direction of ice movement, formed in newly deposited till or older drift.  They range in height from a few centimeters to 25 m, and in length from a few meters to 20 km.  GG
A local-scale topographic pattern of recurring, small, sinuous or arcuate ridges separated by shallow troughs irregularly spaced across low-relief flood plains(slopes generally 2 - 6 %); the effect is one of a subdued, sinuously undulating surface that is common on active, meandering flood plains.  Micro-elevational differences between bars and channels generally range from <0.5 to 2 m and are largely controlled by the competency of the stream.  The ridge-like bars often consist of somewhat coarser sediments compared to the finer textured sediments of the micro-low troughs.  Compare - meander scroll, meander belt.  SW
A long narrow body of outwash confined within a valley beyond a glacier; it may, or may not, emerge from the valley and join an outwash plain.  GG
A long, broad low ridge or embankment of sand and coarse silt, built by a stream on its flood plain and along both sides of its channel, especially in time of flood when water overflowing the normal banks is forced to deposit the coarsest part of its load. It has a gentle slope away from the river and toward the surrounding floodplain, and its highest elevation is closest to the river bank.  Compare - levee, artificial levee, meander belt.  GG
A long, deep, narrow, very steep-sided valley cut primarily in bedrock with high and precipitous walls in an area of high local relief (e.g., mountain or high plateau terrain), often with a perennial stream at the bottom; similar to but larger than a gorge.  Compare - gorge, box canyon, slot canyon.  SW, HP & GG
A long, narrow depression or troughlike hollow between the edge of a retreating glacier and the wall of its valley, or between the front of a moraine and its outwash plain.  GG
A long, narrow elevation of the land surface, usually sharp crested with steep sides and forming an extended upland between valleys.  The term is used in areas of both hill and mountain relief.  HP
A long, narrow sand dune, usually symmetrical in cross profile, oriented parallel to the prevailing wind direction ; it is wider and steeper on the windward side but tapers to a point on the lee side.  It commonly forms behind an obstacle in an area where sand is abundant and the wind is strong and constant.  Such dunes can be a few meters high and up to 100 km long.  Compare - seif dune, transverse dune.  GG
A long, narrow, deep and tortuous channel or drainageway with sheer rock walls eroded into sandstone or other sedimentary rocks, especially in the semi-arid western USA (e.g. Colorado Plateau); subject to flash flood events; depth to width ratios exceed 10:1 over most of its length and can approach 100:1; commonly containing unique ecological communities distinct from the adjacent, drier uplands.  SW
A long, narrow, sandy island that is above high tide and parallel to the shore and that commonly has dunes, vegetated zones, and swampy or marshy terrains extending lagoonward from the beach.  Compare  barrier beach.  GG
A long, narrow, sandy island, representing a broadened barrier beach that is above high tide and parallel to the shore, and that commonly has dunes, vegetated zones, and swampy terrains extending lagoonward from the beach.  Also a long series of barrier beaches.  Compare - barrier beach. GG
A long, narrow, sinuous and steep-sided ridge composed of irregularly stratified sand and gravel  deposited as the bed of  a  stream flowing in an ice tunnel within or below the ice (subglacial) or between ice walls on top of the ice of a wasting glacier, and  left behind as high ground when the ice melted.  Eskers range in length from less than a kilometer to more than 160 kilometers, and in height from 3 to 30 meters.   Compare - glaciofluvial deposits, kame, crevasse filling, outwash.  SW
A long, narrow, vegetated marine beach ridge or sandy hummock, 1 to 6 m high, forming roughly parallel to a prograding shoreline, seaward of marsh and mud-flat deposits, enclosed on the seaward side by fine-grained sediments, and resting on foreshore or mud-flat deposits.  It is well drained, often supporting trees on higher areas.  Widths range from 45 - 450 m and lengths may exceed several tens of kilometers.  GG
A long, narrow, winding, U-shaped and steep-walled, generally deep inlet or arm of the sea between high rocky cliffs of slopes along a mountainous coast.  Typically it has a shallow sill or threshold of solid rock or earth material submerged near its mouth and becomes deeper far inland.  A fjord usually represents the seaward end of a deep, glacially excavated valley that is partially submerged by drowning after melting of the ice.  GG
A long, shallow, round-bottomed groove, furrow, trough, or corridor excavated in the desert floor by wind abrasion, and separating two yardangs.  GG
A low "island" of land surrounded by a younger (more recent) lava flow.  Compare - steptoe.  MA
A low density, dilute, turbulent pyroclastic flow, usually very hot, composed of a generally unsorted mixture of gases, ash, pumice and dense rock fragments that travels across the ground at high speed and less constrained by topography than a pyroclastic flow; several types of pyroclastic surges can be specified (e.g. base surge, ash-cloud-surge).  Compare - pyroclastic flow.  SW, SN, GG
A low hill or mound built up of siliceous sinter around the orifice of a geyser. GG
A low mound, knob, hummock, or short irregular ridge, composed of stratified sand and gravel deposited by a subglacial stream as a fan or delta at the margin of a melting glacier; by a supraglacial stream in a low place or hole on the surface of the glacier; or as a ponded deposit on the surface or at the margin of stagnant ice.  Compare - crevasse filling, kame moraine, kame terrace, esker, outwash.  GG
A low mound, ridge, bank or hill of loose, windblown, subaerially deposited, granular material (generally sand), either bare and capable of movement from place to place, or covered and stabilized with vegetation,  but always retaining its characteristic shape.  (See barchan dune, parabolic dune, parna dune, shrub-coppice dune, seif dune, transverse dune).  SW & GG
A low point on a ridge or interfluve, generally a divide (pass, col) between the heads of streams flowing in opposite directions.  Compare - summit, crest.  HP
A low relief, broad volcanic crater formed by multiple, shallow explosive eruptions.  It is surrounded by a crater ring in the form of low ramparts of gently dipping (i.e. < 25 degrees), well-bedded ejecta; may be filled by water.  SW & GG
A low step with a straight or lobate front, the latter reflecting local differences in rate of flow.  A solifluction terrace may have bare mineral soil on the upslope part and 'folded under' organic matter in both the seasonally thawed and the frozen soil.  NRC
A low, essentially continuous mound of beach or beach-and-dune material heaped up by the action of waves and currents on the backshore of a beach, beyond the present limit of storm waves or the reach of ordinary tides, and occurring singly or as one of a series of approximately parallel deposits.  The ridges are roughly parallel to the shoreline and represent successive positions of an advancing shoreline.  GG
A low, generally broad plain that has as its margin an oceanic shore and its strata horizontal or gently sloping toward the water, and generally represents a strip of recently prograded or emerged sea floor; e.g. the coastal plain of the southeastern U.S. which extends for 3000 km from New Jersey to Texas.  GG
A low, outspread mass of loose materials and/or rock material, commonly with gentle slopes, shaped like an open fan or a segment of a cone, deposited by a stream (best expressed in semiarid regions) at the place where it issues from a narrow mountain or upland valley; or where a tributary stream is near or at its junction with the main stream.  It is steepest near its apex which points upstream and slopes gently and convexly outward (downstream) with a gradual decrease in gradient.  GG
A low, smooth, elongated oval hill, mound, or ridge of compact till that has a core of bedrock or drift.  It usually has a blunt nose facing the direction from which the ice approached and a gentler slope tapering in the other direction.  The longest axis is parallel to the general direction of glacier flow.  Drumlins are products of streamline (laminar) flow of glaciers, which molded the subglacial floor through a combination of erosion and deposition.  Compare - drumlinoid ridge.  SW,  HP, & GG
A marine or lacustrine landform area that generally parallels the shore and extends seaward or lakeward from the low water line to beyond the breaker zone including longshore bars. In the nearshore zone, waves steepen, break, and reform during passage to the beach. Sediment transport occurs both along and perpendicular to the shore via wave and current action.
A mass of poorly sorted angular boulders and fine material, with interstitial ice a meter or so below the surface (ice-cemented) or containing a buried ice glacier (ice-cored).  It occurs in a permafrost area, and is derived from a cirque wall or other steep cliff.  Rock glaciers have the general appearance and slow movement of small valley glaciers, ranging from a few hundred meters to several kilometers in length, and having a distal area marked by a series of transverse, arcuate ridges.  GG
A microfeature in the form of a long, irregular, sharp-crested, undercut ridge between two round-bottomed troughs, carved on a plateau or unsheltered plain in a desert region by wind erosion, and cut into soft but coherent deposits (such as clayey sand); it lies in the direction of the dominant wind, and may be up to 6 m high and 40 m wide.
A microfeature pattern of soils composed of a succession of microbasins and microknolls on level areas, or of microtroughs and microridges parallel to the slope on sloping areas, and produced by expansion / contraction and shear / thrust processes with changes in moisture.  Found in soils containing large amounts of smectitic clay that swell and shrink considerably with wetting and drying. Various types of gilgai can be recognized based on the dominant shape of micro-highs and micro-lows: circular gilgai, elliptical gilgai, and linear gilgai.  Also referred to, in part or in total, as crabhole, Bay of Biscay, or hushabye in older literature.  SW & GSST
A more or less well defined area that is covered with volcanic rocks of much more diverse lithology and distribution than a lava field, or that is so modified by age and erosion that it's original topographic configuration, composition and extent is uncertain.  Compare - lava field, lava plain.  SW
A mound or stratum of refuse (broken pots, ashes, food remains, etc.) normally found on the site of an ancient settlement.  GG
A mud-rich strand plain, occupied by cheniers and intervening mud-flats with marsh and swamp vegetation.  Compare - chenier, strand plain.  GG
A narrow shelf, partly cut and partly built, produced along a lake shore in front of a scarp line of low cliffs and later exposed when the water level falls.  GG
A narrow, elongate, coarse-textured ridge that once rose near to, or barely above, a pluvial or glacial lake and extended generally parallel to the shore but was separated from it by an intervening trough or lagoon; both the bar and lagoon are now relict features.  GG
A narrow, elongate, intertidal, sloping landform that is generally parallel with the shoreline located on the lagoon or estuary side of the barrier island, or spit.  Compare  barrier island.
A narrow, jagged mountain crest, often above the snowline, sculptured by alpine glaciers and formed by backward erosion of adjoining cirque walls.  HP
A natural surface channel in a lava flow that never had a roof, formed by the surficial draining of molten lava rather than by erosion from running water; also called lava channel.  Compare - mawae, lava tube.  SW
A natural, geothermally heated spring whose temperature is above that of the human body.  Compare - geyser, mud pot.  GG
A natural, hollow tunnel beneath the surface of a solidified lava flow through which the lava flow was fed; the tunnel was left empty when the molten lava drained out.  MA & GG
A natural, seasonal pond in a small closed depression (micro-low) which supports a semi-aquatic or aquatic ecosystem adapted to annual cycles of standing water in the springtime followed by drying in the summer / autumn; commonly recognized in CA.  SW
A natural, subaqueous ridge, bank, or bar consisting of, or covered by, sand or other unconsolidated material, rising from the bed of a body of water (e.g. estuarine floor) to near the surface Compare  dredge-deposit shoal, reef.  GG
A nearly level area, including the lower part (footslope) of a micro-high, that is a transition zone between the slightly elevated micro-high (i.e. microknoll; mound in Russia) and the outer edge of an adjacent micro-low (i.e. microbasin, microtrough; depression in Russia) in gilgai.  Where present, it can make up a majority of the ground surface area in gilgai; called slope in Russia.  Compare - ephemeral stream.  HP
A nearly level surface marking the floor of an extinct lake filled by well-sorted, generally fine-textured, stratified deposits, commonly containing varves.  GG
A nearshore zone that is presently subaerially exposed due to isostatic rebound or glacial lake drainage. A raised beach marks the former landward edge of a relict near shore zone and former longshore may exist in the offshore position. Surficial sediments may display evidence of wave and current action such as sorting or particle-size discontinuities.
A nutrient-rich wetland with a surface pattern of ridges and depressions.
A part of a mountain between the summit and the foot.  Compare - mountainflank, hillslope.  GG
A passage, incision, or space from which material has been excavated, such as a road cut or railroad cut.  GG
A peatland with roughly parallel, narrow ridges of peat dominated by peat vegetation interspersed with slight depressions, many of which contain shallow pools.  The ridges are at right angles to low (< 2o) slopes.  They are typically 1 to 3 m wide, up to 1 m high and may be over 1 km long.  The ridges are slightly elevated and are better drained allowing shrubs and trees to grow.  They are best developed in areas of discontinuous permafrost.
A permanently submerged extension of the back-barrier beach that generally parallels the boundary between estuary and the barrier island.  Compare  submerged mainland beach, barrier beach.
A permanently submerged extension of the mainland beach that generally parallels the boundary between an estuary or lagoon and the mainland.  Compare  submerged back-barrier beach, barrier beach.
A place in a stream bed swept (scoured) by running water, generally leaving a gravel bottom.  GG
A platform-like, nearly level to gently inclined erosional surface developed on resistant strata in areas where valleys are cut in alternating strong and weak layers with an essentially horizontal attitude.  Structural benches are bedrock controlled, and in contrast to stream terraces, have no geomorphic implication of former, partial erosion cycles and base-level controls, nor do they represent a stage of flood-plain development following an episode of valley trenching.  Compare - ledge; see scarp.  HP
A platform-like, nearly level to gently inclined erosional surface developed on resistant strata in areas where valleys are cut in alternating strong and weak layers with an essentially horizontal attitude.  Structural benches are bedrock controlled, and in contrast to stream terraces, have no geomorphic implication of former, partial erosion cycles and base-level controls, nor do they represent a stage of flood-plain development following an episode of valley trenching.  Compare - pediment, ledge; see scarp.  HP
A polygon whose center is depressed relative to its boundary.  Compare - high-center polygon.  NRC
A polygon whose center is raised relative to its boundary.  Compare - low center polygon.  NRC
A portion of a hillslope or mountainslope mantled by scree and lacking an up-slope rockfall source (i.e. cliff).  Compare - talus slope, scree, talus.  SW
A portion of a hillslope or mountainslope mantled by talus and lying below a rockfall source (cliff).  Compare - scree slope, scree, talus.  SW
A prograded shore built seaward by waves and currents, and continuous for some distance along the coast.  It is characterized by subparallel beach ridges and swales, in places with associated dunes.  GG
A prominent, isolated, residual knob, hill, or small mountain, usually smoothed and rounded, rising abruptly from an extensive lowland erosion surface in a hot dry region; generally bare and rocky although the lower slopes are commonly buried by colluvium.  Compare - monadnock, nunatak.  GG
A quiet part of, or a still body of water in a stream.  Compare - backswamp.  GG
A raised, generally horizontal strip of earth and/or rock bounded by a down-slope berm or retaining wall, constructed along a contour on a hillslope to make land suitable for tillage and to prevent accelerated erosion; common in steep terrain, both archaic (e.g. Peru) and modern (e.g. Nepal).  Compare - conservation terrace.  SW & GSST
A region of semi-stabilized sand dunes or sandy hills, either covered with vegetation or bare, as in north-central Nebraska and the midlands of the Carolinas.  GG
A region or landscape characterized by mountains and their intervening valleys; a generic name for any group, cluster, or sequence of mountains or narrowly spaced mountain ridges, with or without peaks, closely related in position, orientation, direction, formation, or age, and whose summits commonly exceed 300 m  (approx. 1000 ft).  Compare - foothills, hills, mountain range, mountain system.    SW.
A relatively continuous and steep slope or cliff produced by erosion or faulting and that topographically interrupts or breaks the general continuity of more gently sloping land surfaces .  The term is most commonly applied to cliffs produced by differential erosion.  Synonym: "scarp." SW & HP
A relatively deep, steep-banked lake or pool occupying an ice-gouged rock basin amid glaciated mountains.  A cirque lake.  GG
A relatively flat, low-lying area, commonly including pools of water, separating the exposed or seaward edge of a barrier beach or barrier island from the lagoon behind it.  An assemblage of both deflation flats left behind migrating dunes and /or storm washover sediments; may be either barren or vegetated.  Compare  barrier beach, back-barrier flat.  GG
A relatively large depression resulting from the excavation of material and redistribution of overburden associated with surficial mining operations.  Compare - quarry, surface mine.  SW & GG
A relatively level or bench-like surface formed by the coalescence of several cirques.  GG & SW
A relatively shallow trench or depression cut into drift and other loose material, or in bedrock, by a subglacial stream not loaded with coarse sediment that may or may not be part of the present day drainage pattern.  GG
A relatively small, concordant and / or discordant plutonic rock body exposed at the land surface, with an aerial extent < 40 sq. mi. (100 km2) and no known bottom.  Compare - batholith.  GG
A relict (inactive) delta composed of glaciofluvial sediments formed where a sediment laden outwash river emptied into an open lake, commonly a proglacial lake.  Sediment attributes include very gently dipping topset beds (coarser textures) and steeply dipping foreset beds (finer textures).  SW & GM
A relict glaciofluvial terrace that retains its original attitude, composed of undistorted outwash sediments and depositional structures and whose surface is pock-marked with numerous potholes or kettle depressions.  Compare - collapsed outwash plain.  SW
A relict, wave-cut terrace (solution platform?) formed across soluble bedrock (e.g. limestone), and subsequently subaerially weathered by solution resulting in prominent karst features (e.g. sinkholes, karst valleys, solution pipes, etc.); a type of marine terrace, extensive in the Florida peninsula.  Dunefields and sand sheets of reworked coastal/fluviomarine sands are common capping materials.  SW
A ridge-like accumulation that is being or was produced at the outer margin of an actively flowing glacier at any given time; a moraine that has been deposited at the outer or lower end of a valley glacier.  Compare - terminal moraine, recessional moraine, ground moraine.  GG
A ridge-like moraine carried on and deposited at the side margin of a valley glacier.  It is composed chiefly of rock fragments derived from valley walls by glacial abrasion and plucking, or colluvial accumulation from adjacent slopes.  GG
A ridge-like or mound-like structure, layered or massive, built by sedentary calcareous organisms, especially corals, and consisting mostly of their remains; it is wave-resistant and stands above the surrounding contemporaneously deposited sediment.  Reefs may also include a mass or ridge of rocks, especially coral and sometimes sand, gravel, or shells, rising above the surrounding estuary, sea or lake bottom to, or nearly to, the surface.  SW & GG
A ripple that is more than 30 m in length; e.g., the jokulhlaup derived giant ripples in Camas Prairie, MT.; it usually exhibits superimposed megaripples.  Compare - ripple mark.  GG
A rock drumlin or drift deposit whose form approaches but does not fully attain that of a classic drumlin, even though it seemingly results from similar processes of moving ice.  Compare - drumlin, interdrumlin.  SW & GG
A rough or broken margin of an eroded fan remnant highly dissected by ravines and gullies that can be just a fringe or make up a large part of an eroded alluvial fan; its bounding escarpments (risers), originally formed by inset channels, have become highly dissected and irregular such that terrace components (tread and riser) have been consumed or modified and replaced by hillslope positions and components (shoulder, backslope, footslope, etc.); sometimes referred to as fan remnant sideslopes (FFP).  Compare - eroded fan remnant.  SW & FFP
A roughly linear, deep water area formed by a dredging operation for navigation purposes (after Wells et al., 1994; dredged hole).  Compare  dredge-deposit shoal.
A rugged, irregular wall of broken floating ice buckled upward by the lateral pressure of wind or current forcing or squeezing one floe against another, or against a shore; it may extend for kilometers in length and up to 30 m in height.  Along shores they are lower (< 10 m tall)  and  contribute to the temporary or permanent formation of a beach berm or a rim of boulders and stones.  SW & GG
A sand dune with a long, scoop-shaped form, convex in the downwind direction so that its horns point upwind, whose ground plan, when perfectly developed, approximates the form of a parabola.  GG
A sand or gravel bar or barrier that connects an island with the mainland or with another island.  GG
A sand sheet blown up onto the lower slopes of a bedrock hill or mountain and forming an inclined plane, sometimes filling small mountain-side valleys and even crossing low passes.  Compare - climbing dune, sand sheet.  FFP & SW
A sand-covered plain which may originate by deflation of sand dunes, and whose lower limit of erosion is governed by the water table.  Also spelled sandplain.  GG.
A saucer-, cup-, or trough-shaped hollow or depression formed by wind erosion, on a pre-existing dune or other sand deposit, especially in an area of shifting sand, loose soil, or where protective vegetation is disturbed or destroyed; the adjoining accumulation of sand derived from the depression, where recognizable, is commonly included.  Commonly small, but some blowouts may be many kilometers in diameter.  Compare - deflation basin.  GG
A semi-conical type of alluvial fan with very steep slopes; it is higher, narrower, and steeper (e.g., > 40% slopes) than a fan, and composed of coarser, and thicker layers of material deposited by a combination of alluvial episodes and to a much lesser degree, landslides (e.g., debris flow).  Coarsest materials tend to concentrate at the cone apex.  Compare - alluvial fan, talus cone.
A separate, distinct lobe of lava that issues from the main body of a lava flow; a specific outpouring of lava, a few centimeters to several meters thick and of variable lateral extent, that forms a subdivision within a single flow.  A series of overlapping lava flow-units together comprise a single lava flow.  Also called flow unit.  Compare - lava flow.  GS & GG
A shallow depression, generally less than 10 hectares in area, occurring on disintegration moraines and commonly containing an intermittent or seasonal pond or marsh.  GG
A shallow, intermittent lake in a arid or semi-arid region, covering or occupying a playa in the wet season but drying up in summer; an ephemeral lake that upon evaporation leaves or forms a playa.  GG
A shallow, non-cliffed depression or hollow on a mountain side permanently or intermittently occupied by a snow bank or snow patch and produced by nivation.  If the snow completely melts each summer the hollow is deepened; otherwise not; may be a cirque precursor if further enlarged and deepened by alpine glaciation.  GG
A sharp break or opening in a mountain ridge, or a short pass through a mountain range; e.g., a wind gap.  GG
A sharp-crested, symmetric ridge formed by highly tilted resistant rock layers; a type of homocline produced by differential erosion of interlayered resistant and weak rocks with dips greater than about 25 degrees (or approximately > 45 % slopes).  Compare - homoclinal ridge, cuesta.
A sheet-like mantle of relatively young alluvium and soils covering part of an older fan piedmont (and occasionally alluvial fan) surface, commonly thicker and further down slope (e.g., mid-fan or mid-fan piedmont) than a fan collar.  It somewhere buries an older soil that can be traced to the edge of the fan apron where the older soil emerges as the land surface, or relict soil.  No buried soils should occur within a fan-apron mantle itself.  Compare - fan collar.  FFP
A short, narrow waterway connecting a bay, lagoon, or similar body of 
water.  Compare  tidal inlet.  GG
A short, straight ridge of stratified sand and gravel believed to have been deposited in a crevasse of a wasting glacier and left standing after the ice melted; a variety of kame.  May also occur as long, sinuous ridges and linear complexes of till or drift.  GG
A single, large mass consisting of a succession of mountains or narrowly spaced mountain ridges, with or without peaks, closely related in position, direction, orientation, formation, and age; a component part of a mountain system.  Compare - mountain system, mountains.  GG
A slope of the land surface, roughly determined by and approximately conforming to the dip of underlying bedded rocks; (i.e. the long, gently inclined surface of a cuesta).  Compare - scarp slope.  HP
A slope or wall portion of a cut excavated into unconsolidated material (regolith) or bedrock, as in a borrow pit.  It may stand nearly vertical resulting from collapse as the base is undercut during excavation or by erosion, or it may be reduced by subsequent erosion to a more subdued angle by slope wash.  Compare - cut, beveled cut, roadcut.  SW
A sloping and sometimes high relief landform composed predominantly of glaciofluvial sediment that delimits a former ice-margin of a relatively static, rapidly wasting glacier.  A steep ice-contact slope forms the ice-proximal face of the landform; a more gently sloping surface dips away on the distal slope, if not slumped.  Compare - ice-margin complex.  SW
A small channel with steep sides caused by erosion and cut in unconsolidated materials by concentrated but intermittent flow of water usually during and immediately following heavy rains or after ice / snow melt.  A gully generally is an obstacle to wheeled vehicles and too deep (e.g., >  0.5 m) to be obliterated by ordinary tillage; (a rill is of lesser depth and can be smoothed over by ordinary tillage).  Compare - rill, ravine, arroyo, swale, and draw.  HP & GSST
A small channel with steep sides caused by erosion and cut in unconsolidated materials by concentrated but intermittent flow of water usually during and immediately following heavy rains or after ice / snow melt.  A gully generally is an obstacle to wheeled vehicles and too deep (e.g., >  0.5 m) to be obliterated by ordinary tillage; (a rill is of lesser depth and can be smoothed over by ordinary tillage).  Compare - rill, ravine, arroyo, swale, draw.  HP & GSST
A small dome or mound on the surface of a lava flow formed by the buckling of the congealing crust near the edge of a flow caused by differences in  flow rates of the cooler crust above and the hotter, more fluid lava below.  Dimensions commonly range from < 1 m to 5 m in height, 3 to 10 m in width and 30 to 40 m in length.  Some tumuli are hollow.  Compare - pressure ridge [volcanic].  SW, GG, and GS
A small elongate protruding knob or hillock of bedrock, so sculptured by a large glacier as to have its long axis oriented in the direction of ice movement, an upstream (stoss or scour) side that is gently inclined, smoothly rounded, and striated, and a downstream (lee or pluck) side that is steep and rough.  It is usually a few meters in height, length, and breadth.  GG
A small human-made hill, composed either of debris accumulated during successive occupations of the site or of earth heaped up to mark a burial site. GG
A small mound of fresh soil material formed by frost action.  A type of nonsorted circle commonly found in fine-grained sediment underlain by permafrost, or formed in areas affected by seasonal frost.  Compare - patterned ground.  NRC
A small stream channel; narrow, steep-sided, commonly V-shaped in cross section and larger than a gully, cut in unconsolidated materials.  General synonym (not preferred) - gulch.  Compare - arroyo, draw, gully.  HP
A small tubular opening or chimney formed by fluid lava congealing and mounding around a fumarolic vent in a basaltic lava flow, usually about 1 m in diameter and up to 5 m high, although in the northwestern USA where spiracles are common they generally are 10 m in diameter and 12 m high or more; formed by a gaseous explosion in lava that is still fluid, probably due to steam generated from underlying wet material; smoother lava clots and drapes than a spatter cone.   Compare - spatter cone.  SW, GS, & GG
A small, high-angle, tertiary spur ridge or mini-interfluve that is a constituent part of rib & groove topography; (slopes generally 20 - 90 %, or more); common on the mid and lower hillslopes of well dissected uplands.  Compare - finger ridge, groove, rib and groove topography.  SW
A small, irregular knob of earth (earth hummock) or turf (turf hummock).  Neither type of hummock is diagnostic of permafrost, but both are most common in subpolar or alpine regions.  Both require vegetative cover.  GG
A small, low, rounded hill rising above adjacent landforms.  HP
A small, narrow sheltered bay or recess in an estuary, often inside a larger embayment.  Compare  estuary.  GG
A small, natural body of standing water, usually fresh; e.g. a stagnant body of water in a marsh, or a transient puddle in a depression following a rain.  GG
A small, natural watercourse cut in unconsolidated materials, generally more open with a broader floor and more gently sloping sides than an arroyo, ravine or gulch, and whose present stream channel may appear inadequate to have cut the drainageway that it occupies.  SW
A small, natural, narrow drainageway on high angle slopes which separate small, tertiary spur ridges or mini-interfluves and is a constituent part of rib & groove topography; common in well dissected uplands.  Compare - rib.  SW
A small, partially or completely closed depression formed by movement along a strike-slip fault, or by mass movement (i.e., landslide) that may or may not temporarily pond water from impounded drainage or surface runoff.  For example, a closed depression formed between a scarp or headwall and an adjacent rotated slump block of a landslide.  SW
A small, permanent body of water in a semi-closed or closed depression formed by movement along a strike-slip fault or by mass movement (i.e., landslide) that ponds water from impounded drainage or surface runoff.  Also spelled sagpond.  SW & GG
A small, sinuous or arcuate ridge-like lineation on a flood plain and separated from others like it by small channels or troughs; caused by fluvial processes and common to flood plains and young alluvial terraces, and is a constituent part of bar & channel topography.  Compare - meander scroll.  SW
A small, steep-sided cone (e.g., 3 - 15 m high, or more) built up on a lava flow, usually pahoehoe, composed of clots of lava ejected with escaping gases from a vent or fissure which spatters and congeals as it hits the ground to form a small cone; rougher lava clots than a spiracle.  Compare - spiracle.  SW
A small, streamlined dune that forms around brush and clump vegetation.  GG
A solidified body of rock formed from the lateral, surficial outpouring of molten lava from a vent or fissure, often lobate in form.  Compare - `a`a lavaflow, lava flow unit, pahoehoe lava flow. GG
A steep (e.g. 30-40 degrees), cone-shaped landform at the base of a cliff or escarpment, that heads in a relatively small declivity or ravine, and composed of poorly sorted rock and soil debris that has accumulated primarily by episodic rockfall or, to a lesser degree, by slope wash. Finest material tends to be concentrated at the apex of the cone.  Not to be confused with an alluvial cone; a similar feature but of fluvial origin, composed of better stratified and more sorted material, and that tapers up into a more extensive drainageway.  Compare - alluvial cone, beveled base, talus slope.
A steep escarpment of predominantly glaciofluvial sediment that was deposited against a wall of glacier ice, marking the position of a relatively static ice-margin; an irregular scarp against which glacier ice once rested.  Compare - head-of-outwash.  SW & GG
A steep slope at the head of a valley; e.g. the rock cliff at the back of a cirque.  Compare - cirque headwall. GG
A steep surface on the displaced material of a landslide, produced by differential movements within the sliding mass.   Compare - main scarp, toe.  CV
A steep-sided mass of rock rising above its surroundings on all sides from a slope or hill.  GG
A steep-sided, bowl-shaped depression commonly without surface drainage (closed depression) in drift deposits, often containing a lake or swamp, and formed by the melting of a large, detached block of stagnant ice that had been wholly or partly buried in the drift.  Kettles range in depth from 1 to tens of meters, and with diameters up to 13 km.  Compare - pothole.  GG
A steep-sided, rounded extrusion of highly viscous lava squeezed out from a volcano, and forming a dome-shaped or bulbous mass of congealed lava above and around the volcanic vent.  GG
A steep-walled, half bowl-like recess or hollow, crescent-shaped or semicircular in plan, commonly situated at the head of a  glaciated mountain valley or high on the side of a mountain, and produced by the erosive activity of a mountain glacier.  It often contains a small round lake (tarn).  Compare - cirque floor, cirque platform, cirque wall.  SW & GG.
A steeply sloping upland composed of hills with relief of  30 up to 300 meters and fringes a mountain range or high-plateau escarpment.    Compare - hill, mountain, plateau.  HP
A step-like surface, bordering a valley floor or shoreline, that represents the former position of a flood plain, or lake or sea shore.  The term is usually applied to both the relatively flat summit surface (tread), cut or built by stream or wave action, and the steeper descending slope (scarp, riser), graded to a lower base level of erosion.  Compare - stream terrace, flood-plain step.  HP.  [ soil survey] Practically, terraces are considered to be generally flat alluvial areas above the 100 yr. flood stage.  SW
A straight, open trench about 3 to 10 m wide in a karst area, formed by vertical and lateral solution zones developed along bedrock fractures; also called (not preferred) bogaz, zanjon (Puerto Rico).  Compare - solution fissure, karst valley.  SW & GG
A stream drainage along the side or front of a glacier.  Relict ice-marginal streams are used to trace the former position of a glacier; also called ice-marginal drainage.  SW & GG
A stream or reach of a stream that flows continuously throughout the year and whose surface is generally lower than the water table adjacent to the region adjoining the stream.  Compare - Ephemeral stream, Intermittent stream.  GG
A stream, or reach of a stream, that does not flow year-round  (commonly dry for 3 or more months out of 12) and whose channel is generally below the local water table; it flows only when a) it receives baseflow solely during wet periods, or b) it receives ground-water discharge or protracted contributions from melting snow or other erratic surface and shallow subsurface sources.  Compare - ephemeral stream.  HP
A subaerial mound or ridge that permanently stands above the water composed of dredge spoils; randomly mixed sediments deposited during dredging and dumping.  Compare  dredged channel, dredge-deposit shoal, filled marshland.  SW
A subaerial soil area composed of fill materials  (construction debris, dredged or pumped sandy or shell-rich sediments, etc.) deposited and smoothed to provide building sites and associated uses (e.g. lawns, driveways, parking lots).  These fill materials are typically 0.5 to 3 m thick and have been deposited unconformably over natural soils.  Compare  dredge spoil bank.   SW
A subaerial, gently sloping landform on the lagoon side of the barrier beach ridge composed predominantly of sand washed over or through the beach ridge during tidal surges; a portion of a barrier flat.  Compare  washover-fan flat.
A subaqueous area adjacent to a barrier island or submerged barrier beach that forms a minor embayment or cove within the larger basin.  Compare  cove, mainland cove.
A subaqueous area adjacent to the mainland or a submerged mainland beach that forms a minor recess or embayment within the larger basin.  Compare  cove, barrier cove.
A subaqueous area, substantially shallower than the surrounding area that resulted from the deposition of materials from dredging and dumping (modified from Demas 1998).  Compare  dredged channel, shoal.
A subaqueous extension of a washover-fan flat that slopes toward deeper water of a lagoon or estuary and away from the washover-fan flat.  Compare  washover-fan flat.
A subaqueous, relict depositional landform originally constructed by river or longshore sediments deposits along the outer edge of a wave-cut platform and later submerged by rising sea level or subsiding land surface.  Compare wave  built terrace, wave-cut platform.  GG
A subaqueous, relict erosional landform that originally formed as a wave-cut bench and abrasion platform from coastal wave erosion and later submerged by rising sea level or subsiding land surface.  Compare  wave-built terrace, wave-cut platform.  GG
A subaqueous, sinuous area within a lagoon that likely represents a relict channel (paleochannel) (Wells et al., 1994) that is maintained by strong currents during tidal cycles (Short, 1975).
A subordinate ridge or lesser elevation that projects sharply from the crest or side of a hill, mountain, or other prominent range of hills or mountains.  GG
A subsequent valley eroded in, and developed parallel to the strike of, underlying weak strata; such as a cuesta; a valley that commonly, but not necessarily contains a strike valley.  SW & GG
A subsurface, vertical, cylindrical or cone-shaped hole, formed by dissolution in soluble bedrock (e.g. limestone) and often without surface expression, that is filled with detrital material (e.g. soil) and which serves as a bypass route for internal water flow.
A summit area, or tract of high ground, which can vary from broad to narrow, or a line of separation that constitutes a watershed boundary between two adjacent drainage basins; a divide separates surface waters that flow naturally in one direction from those that flow in a different or opposite direction.  Compare - interfluve  GG
A surface drape or exposure of  up-welled  substratum material forced to the surface and outcropping on a low mound or rim; the surface exposure of a chimney [gilgai]; a type of diapir composed of earthy material.  Compare - chimney, intermediate position [gilgai], gilgai.  SW
A surficial ridge, bank, or bar consisting of sand or other subaqueous deposit that has become permanently exposed by the retreat or lowering of a proglacial lake other body of water.  Compare - longshore bar [relict].  GG
A tabular igneous intrusion that cuts across the bedding or foliation of the country rock.  Compare - sill.  GG
A tabular, igneous intrusion that parallels the bedding or foliation of the surrounding sedimentary or metamorphic rock.  Compare - dike.  GG
A tall, conical column of unconsolidated to semi-consolidated earth materials (e.g. clay till, or landslide debris) produced by differential erosion and usually capped by a flat, hard rock fragment that shields the underlying, softer material from erosion.  It can measure up to 6-20 m in height, and its diameter is a function of the width of the protective boulder.  Compare - hoodoo.
A tall, slender, tapering tower or spire-shaped pillar of rock, either isolated, as on steep slopes or cliffs formed in karst or other massive rocks,  or at the summit of a hill or mountain.    Compare - erosional remnant, hoodoo.  GG
A term applied to many local water features in the lower Mississippi River basin and in the Gulf Coast region of the U.S..  Its general meaning is a creek or secondary watercourse that is tributary to another body of water; especially a sluggish and stagnant stream that follows a winding course through alluvial lowlands, coastal swamps or river deltas. Compare - oxbow, slough.  GG
A term used for one of numerous low circular or oval domes composed of loose, unstratified, gravelly, silty, or sandy material.  The basal diameter varies from 3 meters to more than 30 meters, and the height from 30 centimeters to about 2 meters.  Compare - pimple mound, patterned ground, shrub-coppice dune.  GG
A terminal, end, or recessional moraine formed subaqueously by a glacier that terminated in a water body (e.g., glacial lake, sea, or ocean). A water-lain moraine may occur at the present land surface as a result of isostatic rebound or lake drainage. Compared to a land-based moraine of similar origin, a water-lain moraine displays sediment (till) modification by wave and/or current action and has a somewhat subdued topography.
A terrace-like ridge consisting of stratified sand and gravel (a) deposited by a meltwater stream flowing between a melting glacier and a higher valley wall or lateral moraine, and (b) left standing after the disappearance of the ice.  It is commonly pitted with "kettles" and has an irregular ice-contact slope.  HP
A thin accumulation of stone blocks, typically angular, with only coarse fragments in the upper part, over solid or weathered bedrock, colluvium, or alluvium, without a cliff or ledge above as an apparent source.  Block fields occur on high mountain slopes above tree-line, or in polar or paleo-periglacial regions; they are most extensive along slopes parallel to the contour; and they generally occur on slopes of less than 5%.  Synonym - felsenmeer.  Compare - block stream, talus, scree.  GG
A tidal stream connecting two larger waterways.  GG
A topographic basin excavated and maintained by wind erosion which removes unconsolidated material and commonly leaves a rim of resistant material surrounding the depression.  Unlike a blowout, a deflation basin does not include adjacent deposits derived from the basin.  Compare - blowout.  GG
A topographic feature that remains or is left standing above the general land surface after erosion has reduced the surrounding area; e.g., a monadnock, a butte, or a stack.  GG
A topographically enclosed basin that generally functions as a closed depression and lacks a defined exit channel  Surface water loss may occur via overland flow through a topographic low area or gap in response to large storm events.  Semi-open depressions commonly contain small lakes, ponds, or wet meadows dominated by hydric soils (e.g. in karst valleys, or in low areas on marine terraces with < 1 % slopes).  SW
A tributary valley whose floor at the lower end is notably higher than the floor of the main valley in the area of junction.  GG
A tropical or subtropical marine swamp formed in a silty, organic, or occasionally a coralline substratum and characterized by abundant mangrove trees along the seashore in a low area of salty or brackish water affected by daily tidal fluctuation but protected from violent wave action by reefs or land; dominated by saturated soils, commonly sulfaquents.
A type of  small pit or closed depression (1 to 15 meters deep), generally circular or elliptical, occurring in an outwash plain, a recessional moraine, or a till plain.  GG
A type of basaltic lava flow dominated by `a`a lava and a characteristically rough, jagged, clinkery surface.  Compare - block lava flow, pahoehoe lava flow, pillow lava flow.  GG & MA
A type of basaltic lava flow with a characteristically smooth, billowy or rope-like surface.  Compare - `a`a lava flow, block lava flow, pillow lava flow.
A type of gilgai dominated by circular closed depressions (micro-lows) separated by low mounds (micro-highs); the prevailing type of gilgai on relatively level terrain (slopes < 3 %).  Distance from micro-high to the center of an adjacent microlow is generally 4 - 8 8 m.  Compare - elliptical gilgai, linear gilgai, gilgai.  SW
A type of gilgai dominated by elliptical, closed and semi-closed depressions (micro-lows) separated by low mounds or ridges (micro-highs); the prevailing type of gilgai on mildly sloping terrain (slopes 3 - 8%); as slope increases, basins become more eccentric and the occurrence of interconnected micro-lows increases.  Compare - circular gilgai, linear gilgai, gilgai.  SW
A type of gilgai dominated by parallel micro-low troughs separated by low ridges (micro-highs) and oriented perpendicular to the topographic contour (i.e., up and down slopes); the prevailing type of gilgai on sloping terrain (slopes > 8 %).  Compare - circular gilgai, elliptical gilgai, gilgai.  SW
A type of glacial lake which formed just beyond the margin of an advancing or retreating glacier; generally in direct contact with the ice.  Compare - glacial lake, pluvial lake.  GG
A type of hot spring containing boiling mud, usually sulfurous and often multicolored, as in a paint pot.  Mud pots are commonly associated with geysers and other hot springs in volcanic areas, especially in Yellowstone Natl. Park, WY.  Compare - geyser, hot spring.  GG
A type of hot spring that intermittently erupts jets of hot water and steam, the result of ground water coming in contact with rock or steam hot enough to create steam under conditions preventing free circulation; a type of intermittent spring.  Compare - mud pot, hot spring.  GG
A type of hummock consisting predominantly of a core of silty and clayey mineral soil and showing evidence of cryoturbation.  Earth hummocks are a type of nonsorted circle.  Compare - turf hummock, hummock [patterned ground], non-sorted circle, patterned ground.  NRC
A type of patterned ground consisting of a closed, roughly equidimensional figure bounded by more or less straight sides; some sides may be irregular.  Refer to patterned ground.  Compare - High center polygon, low center polygon, ice wedge polygon, nonsorted polygon.  NRC
A type of patterned ground whose mesh (shape) is dominantly circular and has a nonsorted appearance due to the absence of a boarder of coarse fragments.  Vegetation characteristically outlines the pattern by forming a boardering ridge.  Diameters commonly range from 0.5 to 3 m.  Nonsorted circles include mud boils, earth hummocks, turf hummocks, and frost boils.  Nonsorted circles have various origins.  Some, such as mud and earth hummocks and frost boils, involve cryoturbation activity and differential heave of frost-susceptible materials.  Others, such as mud boils, involve hydraulic pressures and diapir-like displacement of water-saturated sediments.  Compare - sorted circle, frost boil, patterned ground.  NRC and GG
A type of patterned ground whose mesh (shape) is largely circular and has a sorted appearance commonly due to a border of coarse fragments surrounding finer material, occurring either singly or in groups.  Diameters range from a few centimeters to more than 10 meters.  The coarse fragment border may be 35 cm high and 8 to 12 cm wide.  Compare - patterned ground.  GG and NRC
A type of patterned ground; one of the alternating bands of fine and coarse surface material, or of rock or soil and vegetation-covered ground, commonly found on steeper slopes.  It is usually straight, but may be sinuous or branching.  Compare - patterned ground.  GG
A type of sinkhole that is formed by collapse of a cave within the underlying soluble bedrock (e.g., limestone, gypsum, salt).  Compare - solution sinkhole.  SS, WW, & GG
A type of stream terrace, formed as an erosional surface cut on bedrock and thinly mantled ( e.g. < 3 m) with stream deposits (alluvium).
A type of thermokarst depression with steep sides and a flat, grass-covered floor, found in thermokarst terrain, produced by thawing of extensive areas of very thick and exceedingly ice-rich permafrost.  Compare - thermokarst depression.  NRC and GG
A unit of folded strata that dips from the horizontal in one direction only, is not part of an anticline or syncline, and occurs at the earth's surface..  This structure is typically present in plateau areas where nearly flat strata locally assume steep dips caused by differential vertical movements without faulting.  Compare - anticline, syncline, fold.  SW & HP
A unit of folded strata that is concave upward.  In a simple syncline, beds forming the opposing limbs of the fold dip toward its axial plane.  Compare - anticline, monocline.  HP
A unit of folded strata that is convex upward and whose core contains the stratigraphically oldest rocks, and occurs at the earth's surface.  In a single anticline, beds forming the opposing limbs of the fold dip away from its axial plane.  Compare - monocline, syncline, fold.  SW & HP
A valley having a pronounced cross profile suggesting the form of the letter "V", characterized by steep sides and short tributaries; specifically a narrow valley resulting from downcutting by a stream.  The "V" becomes broader as the downcutting progresses.  Compare - U-shaped valley.  GG
A valley having a pronounced parabolic cross profile suggesting the form of a broad letter "U", with steep walls and a broad, nearly flat floor; specifically a valley carved by glacial erosion.  Compare - V-shaped valley.  GG
A valley that contains numerous springs, geysers, and steam fissures fed by the same ground-water flow.  GG
A valley that has developed along a long, narrow continental trough that has down-dropped and is bounded by normal faults; a graben of regional size.  It marks part of a zone along which the entire thickness of the lithosphere has ruptured under crustal extension.  SW & GG
A valley, commonly in karst, that ends abruptly downstream at the point at which its stream disappears underground.  GG
A variety of kegel karst topography, common in the tropics (e.g. Puerto Rico, Pacific Basin Islands) characterized by steep-sided, cone-shaped residual hills separated by star-shaped depressions, broader valleys, or lagoons.  These hills and ridges have steep, convex side slopes and rounded tops that are dissected into secondary karst surfaces with shafts and various forms of karren mircofeatures.  Compare - karst cone, cockpit karst, fluviokarst, sinkhole karst, tower karst.
A vertical, pipe-like tower of solidified lava or consolidated fragmental igneous rock that represents a former volcanic vent whose surrounding material (e.g. tuff and tephra) has been largely removed by erosion.  Compare - plug [volcanic], diatreme.
A very asymmetric sand dune elongated perpendicular to the prevailing wind direction, having a gentle windward slope and a steep leeward slope standing at or near the angle of repose of sand; it generally forms in areas of sparse vegetation. Compare - longitudinal dune. GG
A very small channel with steep sides caused by erosion and cut in unconsolidated materials by concentrated but intermittent flow of water, usually during and immediately following moderate rains or after ice / snow melt.  Generally, a rill is not an obstacle to wheeled vehicles and is shallow enough (e.g., < 0.5 m) to be obliterated by ordinary tillage.  Compare - gully.  SW & GSST
A very small, playa-like, shallow, closed depression typically with a salt-encrusted surface, little or no vegetation in semi-arid to arid climates and infrequently subject to ponding from precipitation events; commonly lacks the component parts of a playa except for a small playa floor.  Compare - playa.
A volcanic dome characterized by an upheaved, consolidated conduit filling.  GG
A volcano having the shape of a very broad, gently sloping dome, built by flows of very fluid basaltic lava or rhyolitic ash flows.  Compare - stratovolcano.   GG & MA
A volcano that is constructed of alternating layers of lava and pyroclastic deposits, along with abundant dikes and sills.  Viscous, acidic lava may flow from fissures radiating from a central vent, from which pyroclastics are ejected.  Compare - shield volcano.  GG
A watercourse that is generally dry but conducts flood waters that have overflowed the banks of a river, commonly from large storms, annual meltwater, or glacial meltwaters.  SW
a) - A category of mass movement processes, associated sediments (slide deposit) or resultant landforms (e.g., rotational slide, translational slide, and snowslide) characterized by a failure of earth, snow, or rock under shear stress along one or several surfaces that are either visible or may reasonably be inferred.  The moving mass may or may not be greatly deformed, and movement may be rotational (rotational slide) or planar (translational slide).    A slide can result from lateral erosion, lateral pressure, weight of overlying material, accumulation of moisture, earthquakes, expansion owing to freeze-thaw of water in cracks, regional tilting, undermining, fire, and human agencies.  Compare -fall, topple, lateral spread, flow, complex landslide.  SW & DV  (b) The track of bare rock or furrowed earth left by a slide.  (c) The mass of material moved in or deposited by a slide.  Compare - fall, flow, complex landslide, landslide.  SW & GG
a) A broad expanse of terrain covered with snow, relatively smooth and uniform in appearance, occurring usually at high latitudes or in mountainous regions above the snowline and persisting throughout year.  b)  A region of permanent snow cover, as at the head of a glacier; the accumulation area of a glacier.  Compare -  glacier.  GG
a) A land area composed of earthy fill material that has been placed and shaped to approximate natural contours, commonly part of land-reclamation efforts after mining operations; b) A land area, commonly submerged in its native state, that has been protected by artificial structures (e.g. dikes) and drained for agricultural or other purposes (e.g. polder).  SW
a) A large assemblage of fluvial landforms (braided streams, terraces, etc.,) that form low gradient, regional ramps along the flanks of mountains and extend great distances from their sources (e.g., High Plains of North America.  SW   b) (not recommended, use flood plain.)  A general, informal term for a broad flood plain or a low-gradient delta.  Compare - alluvial flat.  FFP.
a) A large mass of ice formed, at least in part, on land by the compaction and recrystallization of snow, moving slowly by creep downslope or outward in all directions due to the stress of its own weight, and surviving from year to year.  Included are small mountain glaciers as well as ice sheets continental in size, and ice shelves which float on the ocean but are fed in part by ice formed on land. b)  A stream-like landform having the appearance of, or moving like a glacier; e.g. a rock glacier.  Compare - snowfield, rock glacier.  GG
a) A large-capacity channel constructed to divert floodwaters or excess streamflow from populous, flood-prone areas, such as a bypass route bounded by levees.  b) The part of the flood plain kept clear of encumbrances and reserved for emergency diversion of floodwaters.  GG
a) A modified slope, feature, or land area where much or all of the natural soil has been mechanically removed (e.g. scraped off) due to construction or other management practices.  Compare - truncated soil.  b) A forest soil area where the ground vegetation and root mat have been removed to expose mineral soil in preparation for planting or seeding.  Compare - truncated soil.   SW
a) A narrow gorge or canyon containing an intermittent stream following a zig-zag course, characterized by high, steep rock walls and typically closed upstream by a similar wall, giving the impression, as viewed from its bottom, of being surrounded or "boxed-in" by almost vertical walls.  b) A steep-walled canyon heading against a cliff a dead-end canyon.  GG
a) A natural body of standing fresh water occupying a small surface depression, usually smaller than a lake and larger than a pool.  b) A small artificial body of water, used as a source of water.  Compare  - salt pond.  GG
a) A relict coral reef that stands above sea level and surrounded by water (e.g. Florida Keys).  Carbonate sands rich in coral and shell fragments generally mantle the underlying flat coral platform.  b) An oceanic island formed from coral accumulations lying atop or fringing volcanic peaks or platforms.  SW & GG
a) A seaward end or the widened funnel-shaped tidal mouth of a river valley where fresh water comes into contact with seawater and where tidal effects are evident (e.g., a tidal river, or a partially enclosed coastal body of water where the tide meets the current of a stream).  b) A portion of an ocean or an arm of the sea affected by fresh water.  A drowned river mouth formed by the subsidence of land near the coast or by the drowning of the lower portion of a non-glacial valley due to the rise of sea level.  Compare  lagoon.  GG
a) A walled and rounded or cirque-like opening at the head of a small steep valley.  b) (colloquial - southern Appalachians, USA) A smooth-floored, somewhat oval-shaped "valley" sheltered by hills or mountains; e.g., Cades Cove in eastern Tennessee.  GG
a) A wide, curving open indentation, recess, or arm of a sea (e.g. Chesapeake Bay) or lake (e.g. Green Bay, WI) into the land or between two capes or headlands, larger than a cove [coast], and usually smaller than, but of the same general character as, a gulf.  b) A large tract of water that penetrates into the land and around which the land forms a broad curve.  By international agreement a bay is a water body having a bay mouth that is less than 24 nautical miles wide and an area that is equal to or greater than the area of a semicircle whose diameter is equal to the width of the bay mouth.  Compare  gulf.  GG
a) Any glacier in a mountain range except an ice cap or ice sheet.  It usually originates in a cirque and may flow down into a valley previously carved by a stream.  Compare - continental glacier.  GG  b) (not preferred - refer to U-shaped valley): (relict) - landforms or sediments formed, modified or deposited by a glacier in or on mountains or high hills that has since melted away.  Compare - glacial-valley floor, glacial-valley wall.  SW
All, or a portion of an alluvial fan that is much more extensively eroded and dissected than a fan remnant; sometimes called an erosional fan remnant (FFP).  It consists primarily of a) eroded and highly dissected sides (eroded fan-remnant sideslopes) dominated by hillslope positions (shoulder, backslope, etc.), and b) to a lesser extent an intact, relatively planar, relict alluvial fan "summit" area best described as a tread.  SW & FFP
An abrupt change or inflection in a slope or profile.  Compare - knickpoint, shoulder, escarpment.  (geomorphology)  A marked variation of topography, or a tract of land distinct from adjacent land, or an irregular or rough piece of ground.  Compare - breaks.  GG
An accumulation of boulders or angular blocks, with no fine sizes in the upper part, overlying solid or weathered bedrock, colluvium, or alluvium, and lying below a cliff or ledge from which coarse fragments originate.  Block streams usually occur at the heads of ravines as narrow bodies that are more extensive downslope than along the slope.  They may exist on any slope angle, but ordinarily not steeper than 90 percent slope (approx. 40 degrees).  Compare - block field.  GG
An accumulation of sand commonly in the form of a low mound, produced by the expulsion of liquified sand to the ground surface; sometimes called sand volcanoes (not preferred).  Examples are found on top of some landslide deposits (i.e. spreads) or on the upper surface of highly contorted layers of laminated sediments.  SW & GG
An accumulation of sand that is formed as sand is blown off a mesa top or over a cliff face or steep slope, forming a solid wall, sloping at the angle of repose of dry sand, or a fan extending downward from a re-entrant in the mesa wall.  Compare - climbing dune, sand ramp.  GG
An ancient (relict) beach occurring above the present shoreline and separated from the present beach, having been elevated above the high-water mark either by local crustal movements (uplift) or by lowering of sea level, and often bounded by inland cliffs.  GG
An anthropogenic, nearly level impoundment that is inundated for long periods typically for wetland rice production.  It is applied to areas that have been used in this fashion for a long enough period of time to significantly change the original soil morphology (especially redoximorphic features).  SW
An area covered primarily by lava flows whose terrain can be rough and broken or relatively smooth; it can include vent structures (e.g., small cinder cones, spatter cones, etc.), surface flow structures (e.g., pressure ridges, tumuli, etc.) and small, intermittent areas covered with pyroclastics.  Compare - lava plain, volcanic field.  SW
An area formerly occupied by a glacial lake.  GG
An area of acid, peaty soil, especially that developed from moss, in which the center is higher than the margins.  Compare - pocosin, Carolina Bay, moss peat.  [Note: raised peat bog (not preffered) - refer to highmoor bog].   GG
An area of low, saturated ground, intermittently or permanently covered with water, and predominantly vegetated by shrubs and trees, with or without the accumulation of peat.  Compare - marsh, bog, fen.  GG
An area of smooth or uneven accumulations or piles of waste rock, earthy material, or general refuse that without major reclamation are incapable of supporting plants.  Compare - sanitary landfill, fill.  GSST
An area, generally small, where water outflows slowly at the land surface.  Flow rates for seeps are too small to be considered as springs, but reflow and/or lateral subsurface flow keeps the surface or near surface or near soil saturated during dry periods.  SW & GG
An area, generally small, where water outflows slowly to at the land surface.  Flow rates for seeps are too small to be considered as springs, but reflow and/or lateral subsurface flow keeps the surface or near soil saturated during dry periods.  SW & GG
An area, plain, slope, glacier, or other feature at the base of a mountain; e.g., a foothill or a bajada.  In the United States, the Piedmont (noun) is a low plateau extending from New Jersey to Alabama and lying east of the Appalachian Mountains.  GG
An arrangement of small hills or prominent rocks, in a strongly glaciated area, having gentle slopes on the stoss ("up-ice") side and somewhat steeper, plucked slopes on the lee ("down-ice") side.  This arrangement is the opposite of crag and tail.  Compare - crag and tail, drumlin, drumlinoid ridge, flute.  GG
An artificial embankment constructed along the bank of a watercourse or an arm of the sea, to protect land from inundation or to confine streamflow to it's channel.  GG
An artificial or natural embankment built along the margin of a watercourse or an arm of the sea, to protect land from inundation or to confine streamflow to its channel.  Compare - artificial levee, natural levee.  GG
An assemblage of landforms constructed proximal to a relatively static, rapidly wasting continental glacial margin.  Constituent landforms can include fosse, head-of-outwash, ice-contact slope, ice-contact delta, kame, kame moraine, kettle, outwash fan, small outwash plain, glacial sluiceway, and small proglacial lake.  Moraines, if present, are of limited occurrence (except kame moraines which can be extensive).  Glaciofluvial sediments dominate but glaciolacustrine sediments, till, and diamictons can be present in minor amounts.  SW
An assemblage of moving and/or stabilized dunes, together with sand plains, interdune areas, and the ponds, lakes, or swamps produced by the blocking of steams by the sand.  See dune lake.  SW
An assemblage of moving and/or stabilized sand dunes, together with sand plains, interdune areas, and the pond, lakes, or swamps produced by the blocking of streams by the sand.  See dune lake.  SW.
An asymmetric ridge capped by resistant rock layers of slight to moderate dip,  commonly less than 10 degrees (or approximately < 15 percent slopes); a homocline type produced by differential erosion of interbedded resistant and weak rocks.  A cuesta has a long, gentle slope on one side (dip slope), that roughly parallels the inclined beds, and on the opposite side has a relatively short and steep or cliff-like slope (scarp slope) that cuts through the tilted rocks.  Compare - hogback, homoclinal ridge, mesa, dipslope, scarp slope, cuesta valley.
An asymmetrical depression adjacent to a cuesta that lies parallel to the strike of underlying strata; a type of strike valley.  It's formed by the differential erosion of weaker strata interbedded with more resistant rocks.  It may or may not contain a local drainage network and commonly lies above and is unconnected to the regional drainage system.  Compare - cuesta, valley, trough, hanging valley.  SW
An asymmetrical ridge of local, essentially non-glacial material (such as deformed bedrock, with some drift incorporated in it) that has been pressed up by the shearing action of an advancing glacier.  It is typically 10 - 60 m high, about 150 - 300 m wide, and as much as 5 km long.  Examples are common on the Great Plains where such ridges occur on the sides of escarpments formed of relatively incompetent rocks that face the direction from which the ice moved.  GG
An earthen embankment constructed across a slope for conducting water from above at a regulated flow to prevent accelerated erosion and to conserve water.  Compare - hillslope terrace.  SW & GSST
An elevated, flat-lying, basalt-floored area, with little if any soil cover, sparse vegetation, and usually deep, dry channels scoured into the surface, especially by glacial meltwaters such as the channeled scablands of eastern Washington.  Compare - coulee.  GG
An elliptical dome-like permafrost mound containing alternating layers of ice lenses and peat or mineral soil, commonly 3-10 m high and 2-25 m long, occurring in subarctic bogs of the tundra and often surrounded by water; pl. palsen.  NRC
An elongate, relatively large, externally drained depression of the Earth's surface that is primarily developed by stream erosion or glacial activity.  Compare - basin.  HP
An elongate, structural trough or basin bounded on one side by a normal fault.  It may or may not produce a topographic basin.  Compare - graben.
An elongated block that is bounded on both sides by normal faults that dip away from the interior of the horst.  It is a structural form and may or may not be expressed geomorphically.  GG
An elongated depression of the Earth's surface; carved by a river during the course of it's development.  Compare - valley side, valley floor.  GG
An elongated depression of the Earth's surface; carved by a river during the course of it's development. GG
An elongated hill or ridge of subglacially streamlined drift, having at the stoss end (up-ice) a steep, often precipitous face or knob of ice-smoothed, resistant bedrock (the "crag") obstructing the movement of the glacier, and at the lee end (down-ice) a tapering, streamlined, gentle slope (the "tai;") of intact, weaker rock and / or drift protected by the crag; also called lee-side cone.  Compare - drumlin, drumlinoid ridge, flute, stoss and lee.  GG, SW, & GM
An elongated trough or basin bounded on both sides by high-angle, normal faults that dip towards the interior of the trough.  It is a structural form that may or may not be geomorphically expressed as a rift valley.  Compare - horst.  GG
An elongated uplift of the congealing crust of a lava flow, probably due to the pressure of the underlying, still-flowing lava; commonly < 5 m in height (but range up to 15 m) and < 100 m length (but can exceed 500 m).  Compare - tumulus.  SW, GG, & GS
An elongated, relatively large, externally drained depression of the Earth's surface that is primarily developed by stream erosion or glacial activity.  Compare - basin.  HP
An end moraine that marks the farthest advance of a glacier and usually has the form of a massive arcuate or concentric ridge, or complex of ridges, underlain by till and other drift types.  Compare - end moraine, recessional moraine, ground moraine.  HP and GG
An end or lateral moraine, built during a temporary but significant halt in the final retreat of a glacier.  Also, a moraine built during a minor readvance of the ice front during a period of general recession.  Compare - end moraine, ground moraine, terminal moraine.  GG
An eroded area of a thrust sheet, commonly a basin or valley floor, that exposes the incongruous bedrock stratigraphy beneath the thrust-sheet; a particular structural or stratigraphic relationship is implied, rather than a particular topographic form.  Common in the Appalachian and Rocky Mountain margins.  Synonym: fenster.
An erosion surface of low relief, cut directly into and across bedrock and composed of either bare rock or thinly veneered pedisediment or residuum (e.g. < 1.5 m) over bedrock; it occurs along the flanks of mountain fronts, or at the base of mountains or high hills.  Its surface grades to the backwearing mountain slopes or hillslopes above, and generally grades down to and merges with a lower-lying alluvial plain, piedmont slope or valley floor below.  SW & FFP
An erosional remnant of a terrace which retains the surface form and alluvial deposits of its origin but was not emplaced by, and commonly does not grade to a present-day stream or drainage network.  Compare - alluvial plain remnant.  SW
An erosional remnant of an alluvial plain which retains the surface form and alluvial deposits of its origin but was not emplaced by, and commonly does not grade to a present-day stream or drainage network.  Compare - alluvial plain, erosional remnant, paleoterrace.  SW
An escarpment, cliff, or steep slope of some extent along the margin of a plateau, mesa, terrace, or structural bench.  A scarp may be of any height.  Compare - escarpment.  GG
An essentially flat, terrace-like alluvial surface within a valley that is frequently covered by flood water from the present stream (e.g., below the 100 year flood level); any approximately horizontal surface still actively modified by fluvial scour and/or deposition (i.e., cut and fill and/or scour and fill processes).  May occur individually or as a series of steps.  Compare - stream terrace.  SW & RR
An excavated area where borrow material has been removed typically for construction purposes offsite; also called barrow pit.  GG
An extension of the flood-tidal delta that slopes toward deeper water in a lagoon or estuary, composed of flood channels, inactive lobes (areas of the flood-tidal delta that are not actively accumulating sand as a result of flood tides), and parts of the terminal lobe of the flood-tidal delta (modified from Boothroyd et al., 1985).
An extensive lowland area of coarse textured, glaciofluvial material.  An outwash plain is commonly smooth; where pitted, due to melt-out of incorporated ice masses (pitted outwash plain), it is generally low in relief and largely retains it's original gradient.  Compare - outwash, pitted outwash plain, collapsed outwash plain, kettles.  SW & HP
An extensive lowland area of coarse textured, glaciofluvial material.  An outwash plain is commonly smooth; where pitted, due to melt-out of incorporated ice masses (pitted outwash plain), it is generally low in relief and largely retains its original gradient.  Compare - outwash, pitted outwash plain, kettles.  HP
An extensive, flat to gently undulating area underlain predominantly by till and bounded on the distal end by subordinate recessional or end moraines.  Compare - till, ground moraine.  SW
An extensive, nearly horizontal, barren or sparsely vegetated tract of land that is alternately covered and uncovered by the tide, and consists of unconsolidated sediment (mostly clays, silts and/or sand, and organic materials).  Compare  tidal marsh, wind-tidal flat.  GG
An extensive, nearly level marsh bordering a coast (as in a shallow lagoon, sheltered bay or estuary) and regularly inundated by high tides; formed mostly of unconsolidated sediments (e.g. clays, silts, and/or sands, and organic materials), and the resistant root mat of salt tolerant plants; a marshy tidal flat.  Compare - tidal flat.  GG
An extensive, nearly level, intertidal landform composed of unconsolidated sediments (clays, silts and/or sand and organic materials), a resistant root mat, and vegetated dominantly by hydrophytic plants.  The mineral sediments largely retain pedogenic horizonation and morphology (e.g. argillic horizons) developed under subaerial conditions prior to submergence due to sea level rise; a type of tidal marsh.  Compare  tidal marsh
An homocline that forms an asymmetric ridge with a dip slope commonly between 10 - 25 degrees (or approximately 15 - 45% slopes). A hhomoclinal ridge has steeper dip than a cuesta, but lower dip than a hogback.  Compare - cuesta, hogback.
An impact crater formed by the falling of a large meteorite onto the earth's surface; e.g., Barringer Crater (AZ).  Compare - crater, impact crater.  SW & GG
An informal, general term for (a) the higher ground of a region, in contrast with a low-lying, adjacent land such as a valley or plain.  (b) Land at a higher elevation than the flood plain or low stream terrace; land above the footslope zone of the hillslope continuum.  Compare - lowland.  HP & GG
An inland body of permanently standing brackish or saline water, occupying a depression on the Earth's surface whose water level is commonly influenced by ocean tides through subterranean cavities connecting to nearby lagoons; generally of appreciable size (larger than a pond) and too deep to permit emergent vegetation to take root completely across the expanse of water.  Such water bodies can have unique biota (e.g. sting-less jellyfish of Palau).
An inland body of permanently standing water fresh or saline, occupying a depression on the Earth's surface, generally of appreciable size (larger than a pond) and too deep to permit vegetation (excluding subaqueous vegetation) to take root completely across the expanse of water.
An irregular series of low, broad depressions that form the uppermost reaches of surface drainage networks in low relief/low gradient terrain such as coastal plains, and separated by slightly higher and drier areas (e.g. flatwoods).  They characteristically lack defined stream channels but contribute surface water to the drainage system further downstream through a network of subtle topographic lows.  SW
An island-like area of older rock surrounded by a lava flow.  Compare - kipuka.  HP
An isolated hill or mountain of resistant rock rising conspicuously above the general level of a lower erosion surface in a temperate climate representing an isolated remnant of a former erosion cycle in an area that has largely been beveled to its base level.  Compare - inselberg, nunatak.  GG
An isolated hill, knob, ridge, or peak of bedrock that projects prominently above the surface of a glacier and is completely surrounded by glacier ice.  Compare - inselberg, monadnock.  GG
An isolated tongue-shaped feature up to 25 m wide and 150 m or more long, formed by rapid solifluction on certain sections of a slope showing variations in gradient.  This feature commonly has a steep (e.g. 15-60 degrees) front and a relatively smooth upper surface.  NRC
An isolated, generally flat-topped hill or mountain with relatively steep slopes and talus or precipitous cliffs and characterized by summit width that is less than the height of bounding escarpments, commonly topped by a caprock of resistant material and representing an erosion remnant carved from flat-lying rocks.  Compare - mesa, plateau, cuesta.  HP & GG
An isolated, separate hill or ridge in a karst region consisting of an erosional remnant of limestone or other sedimentary rocks with vertical or near-vertical, convex side slopes and commonly surrounded by an alluvial plain, lagoon, or deep rugged ravines.  Compare - mogote, karst cone.
An open and usually unpaved (unlined), channel or trench excavated to convey water for drainage (removal) from a landscape; smaller than a canal; some ditches are modified natural waterways.  GG
An open and usually unpaved (unlined), channel or trench excavated to convey water for drainage (removal) or irrigation (addition) to or from a landscape; smaller than a canal; some ditches are modified natural waterways.  GG
An opening in earth's surface of a volcanic conduit in the form of a crack or fissure rather than a localized crater; a roughly linear crack or area along which lava, generally mafic and of low viscosity, wells up to the surface, usually without any explosive activity.  The results can be an extensive lava plateau (e.g. Columbia River Plateau).  Compare - crater [volcanic].  SW & GG
An outwash plain marked by many irregular depressions such as kettles, shallow pits, and potholes which formed by melting of incorporated ice masses; much of the gradient and internal structures of the original plain remain intact; many are found in WI, MN, MI, and IN.  Compare - collapsed outwash plain, outwash, pitted outwash.  GG
An outwash plain which forms on glacial ice (inside the glacial margin), and is subsequently let down or collapsed when the underlying ice melts, resulting in contortion or folding of the sediments and sedimentary structures to the extent that little of the original plain or it's gradient remain.  Outwash sediments commonly cap present-day  topography.  Compare - collapsed lake plain, pitted outwash plain.  SW &  CF
An undulating surface of alternating, subparallel, small-scale ridges and depressions, commonly composed of loose sand.  It is produced on land by wind and under water by the agitation of water by currents or wave action, and generally tends at right angles or obliquely to the direction of flow of the moving fluid.  Compare - giant ripple mark.  GG
Any artificial pond or other water-filled excavation for the natural oxidation of sewage or disposal of farm manure.  GG
Any high, very steep to perpendicular or overhanging face of rock or earth; a precipice.  Compare - bluff, beveled base. GG
Any inlet through which water alternately floods landward with the rising tide and ebbs seaward with the falling tide.   Compare  inlet, relict tidal inlet.   GG
Any of various shallow, often oval or elliptical, generally marshy, closed depressions in the Atlantic coastal plain (from southern New Jersey to northeastern Florida, especially developed in the Carolinas) which share an approximately parallel orientation of their long axes.  They range from about 100 meters to many kilometers in length, are rich in humus, and under native conditions contain trees and shrubs different from those of the surrounding areas.  Also called Grady ponds (colloquial: Georgia and Alabama) and Delmarva Bays (colloquial: Maryland).    Compare - pocosin.  GG
Any relatively sunken part of the Earth's surface; especially a low-lying area surrounded by higher ground.  A closed depression has no natural outlet for surface drainage (e.g. a sinkhole).  An open depression has a natural outlet for surface drainage.  Compare - closed depression, open depression.   GG
Areas of bare limestone, usually sculpted by solution erosion into karren of various types and where soils have been stripped off, commonly by glaciation in alpine areas (e.g. Rocky Mountains - USA) and high latitudes, and by water erosion in arid karst areas.  Compare - fluviokarst, glaciokarst, sinkhole karst, karst.
Collapsed basins that are generally closed depressions which are the direct result of surficial subsidence associated with subsurface mining (e.g. long-wall mining).  SW
Excavation areas, open to the sky, usually for the extraction of stone.  GG
Flat, poorly drained area that is subject to periodic or occasional overflow by salt water, containing water that is brackish to strongly saline, and usually covered with a thick mat of grassy halophytic plants; e.g., a coastal marsh periodically flooded by the sea, or an inland marsh, (or salina) in an arid region and subject to intermittent overflow by salty water.  Compare - tidal marsh, mud flat.  GG
Generally a narrow, elongate area that parallels a coastline, commonly cutting across diverse inland landforms, and dominated by landforms derived from active coastal processes which give rise to beach ridges, washover fans, beaches, dunes, wave-cut platforms, barrier islands, cliffs, etc.  SW
Generally a narrow, transverse area that parallels a coastline, commonly crossing cutting across diverse inland landforms, and dominated by landforms derived from active coastal processes which gives rise to beach ridges, overwash fans, beaches, dunes, wave-cut platforms, barrier islands, cliffs, stacks, etc.  SW
Generally a small stream, or upper reach of a stream, that flows only in direct response to precipitation.  It receives no protracted water supply from melting snow or other source, and its channel is, at all times, above the water table.  Compare - arroyo, intermittent stream, perennial stream.  HP
Groups or clusters of closely spaced drumlins or drumlinoid ridges, distributed more or less en echelon, and commonly separated by small, marshy tracts or depressions (interdrumlins).  SW
Hills that are now erosion remnants of a former valley or basin floor, composed mostly of unconsolidated valley / basin fill sediments (e.g. alluvium) and typically lie well above the modern valley floor and flood plain.  Former basin floor surfaces have become dissected and irregular and consist of hillslope positions (shoulder, backslope, etc.) and hill components (interfluve, headslope, etc.); common in large valleys of the western US.
Irregularly spaced, roughly linear to radial depressions or small mounds associated with shallow to deep soil disturbance caused by dragging logs across a slope from where they were cut down to a central processing area such as a log landing during timber harvest operations.  SW
Karst in glaciated terrain developed on bedrock susceptible to dissolution (e.g. limestone), thinly mantled (e.g. < 5 - 30 m) with glacial drift and characterized by surficial, closed depressions formed by post-glacial, subsurface karstic collapse (e.g. sinkholes) rather than by glacial processes (e.g. ice-block melt-out); common in IN, MI.  Compare - karst.
Karst-like topographic features produced in a permafrost region by local melting of ground ice and subsequent settling of the ground.  GG
Lake or pond produced in a permafrost region by melting of ground ice.  HP
Low, arcuate, subaerial ridges of sand developed adjacent to an inlet and formed by the lateral accretion or movement of the channel.
Mountains that formed primarily by block faulting, and commonly exhibit asymmetrical rotation and vertical displacement from a horizontal plane by large, coherent fault-block units hinged along fault lines; common in, but not limited to, the Basin and Range region of the US..  The term is not applied to mountains formed by thrust-faulting.
Narrow salt marsh adjacent to a relatively higher energy environment.
One in a group of small, tertiary spur ridges that form crudely palmate extensions of erosional remnants along the flanks or nose of larger ridges.  Compare - ballena, rib.  SW
One of a series of low, arcuate ridges of sand and gravel developed on the inside of a growing meander by the slow addition of individual accretions accompanying migration of the channel toward the outer bank.  Compare - meander scroll.  GG
One of a series of regular freely developing sinuous curves, bends, loops, turns, or windings in the course of a stream.  GG.
One of a series of vertical open cracks commonly < 0.5 m wide dissolved along joints or fractures, separating limestone pavement (pavement karst) into blocks (clints); also called kluftkarren (not preferred).  Compare - solution corridor, karren.  SW, GG, & WW
One, or a series of flat-topped landforms in a stream valley that flank and are parallel to the stream channel, originally formed by a  previous stream level, and representing remnants of an abandoned flood plain, stream bed, or valley floor produced during a past state of fluvial erosion or deposition (i.e., currently very rarely or never flooded; inactive cut and fill and/or scour and fill processes).  Erosional surfaces cut into bedrock and thinly mantled with stream deposits (alluvium) are called "strath terraces."  Remnants of constructional valley floors thickly mantled with alluvium are called alluvial terraces.  Compare - alluvial terrace, flood-plain step, strath terrace, terrace.  HP & SW
Patterned ground in areas of ice wedges.  These polygons are commonly in poorly-drained areas and may be high-centered or low-centered.  NRC
Periodically wet or continually flooded areas with the surface not deeply submerged.  Covered dominantly with sedges, cattails, rushes, or other hydrophytic plants.  Compare - salt marsh, swamp, bog, fen.  GSST
Raised, linear mounds with subdued, convex slope cross-sections constructed by mounding and shaping spoil material dredged from adjacent drainage ditches and placed over natural soil.  The mounds serve as preferred, better-drained bedding areas for managed timber plantations; common in the lower coastal plains of the Atlantic and Gulf coasts, USA.  SW
refer to block field.  GG
refer to fan remnant
Remnant features of a glacial lake that is now extinct which formed just beyond the margin of an advancing or retreating glacier; generally in direct contact with the ice.  Compare - proglacial lake, pluvial lake.  SW
Repeating, surficial solution channels, grooves or other forms etched onto massive, bare limestone surfaces; types range in depth from a few millimeters to > 1 m and separated by ridges; the total complex (all varieties) of surficial solution forms found on compact, pure limestone.  Many types can be specified.  Compare - solution fissure.  SW & GG
Rock debris, banks, and earthy dump deposits resulting from the excavation of ditches and strip mines.  GSST
Sharp or rugged upward extension of a ridge chain, usually at the junction of two or more ridges; the prominent highest point of a summit area.  HP
Small diameter (e.g. 1-5 m), irregular, hollow, vertical shaft 5-10+ m deep on karst landscapes, typically covered with a thin layer of soil or plant debris that can collapse and expose the shaft to the surface; represents a significant safety hazard.  Locally called stove-pipe sinkholes in Florida (not recommended).  Compare  solution pipe.  SW
Small, irregular step-like forms on steep hillslopes, especially in pasture, formed by creep or erosion of surficial materials that may or may not be induced by trampling of livestock such as sheep or cattle.  Synonyms (not preferred) - catstep, sheep or cattle track.  HP
Small, tighly bunched, parallel ridges or corrugations of lava, commonly < 1 m in amplitude (high) and < 3 m in period (wide) on the surface of corded pahoehoe lava (ropy lava).  SW & GS
Small, trough-like, arcuate or sinuous channels separated by small bars or ridges, caused by fluvial processes and common to floodplains and young alluvial terraces; a constituent part of bar & channel topography. GG, FFP, & SW
The border, margin, edge, or face of a landform, such as the curved brim surrounding the top part of a crater or caldera; specifically the rimrock of a plateau or canyon.  GG
The bottom of a shallow, extinct glacial lake composed of thin (e.g., < 2 m thick), fine-textured, reworked  lacustrine sediments that overlie outwash or till; original lacustrine sediments have been subsequently redistributed primarily by wave action (eroded and / or moved a short distance).  A distinctive lake plain topography is not always present.  It may include subdued, till-capped topographic highs, ringed by shores or strandlines, that were once emergent islands.  Common to MI, OH.  Compare - till-floored lake plain.
The central, channel-like corridor, scar, or depression along which an avalanche has moved.  An eroded surface marked by pits, scratches, and grooves.  GG
The channel of a flat-floored, ephemeral stream, commonly with very steep to vertical banks cut in unconsolidated material, sometimes called a wash.  It is usually dry but can be transformed into a temporary watercourse or short-lived torrent after heavy rain within the watershed.  Where arroyos intersect zones of ground-water discharge, they are more properly classed as intermittent stream channels.  HP
The comparatively flat bottom of a mountain valley predominantly mantled by till but which can grade from glacial scour (scoured rock-outcrop) near it's head to a thick mantle of till, and ultimately merging with alluvium or colluvium further down valley.   Some glacial-valley floors descend downstream in a series of scour-derived steps which may contain sequential tarn lakes (pater noster lakes); (not preferred: colloquial - western USA) sometimes called a trough bottom.  SW
The comparatively level bottom of a cirque, thinly mantled with till and consisting of glacially-scoured knolls and hillocks separated by depressions, flat areas and small lakes (tarn); commonly it is bounded by a slightly elevated rock lip at its exit.  SW & HD
The comparatively steep, glacially scoured, concave sides of a u-shaped, mountain valley mantled by colluvium with little or no till; (not preferred: colloquial - western USA) sometimes called a trough wall.  SW
The concave to relatively flat bottomed, roughly linear depressions ranging from small saddles or swales to small valleys that separate drumlins or drumlinoid ridges in drumlin fields.  Streams, if present, have not had a dominant impact on the formation of the depression.  Compare - drumlin, drumlinoid ridge.  SW
The crescent-shaped, often ephemeral body of standing water situated by the side of a stream in the abandoned channel (oxbow) of a meander after the stream formed a neck cutoff and the ends of the original bend were silted up.  Compare - meander belt, oxbow.  GG
The flat to gently undulating ground underlain or composed of fine-grained sediments deposited in a former lake.
The flat to gently undulating ground underlain or composed of fine-grained sediments deposited in a former lake.  (b) The bottom of a lake; a lake basin.  GG
The flat, usually bare ground situated seaward of a salt marsh and regularly covered and uncovered by the tide; e.g., a mud flat.  GG
The floor of an extinct glacial lake where a thin (e.g. < 2 m), often discontinuous veneer of lacustrine sediments overlies till.  Commonly its topography reflects the underlying, irregular or undulating till surface rather than a distinctive, flat, lake plain surface.  It may include subdued, till-capped topographic highs, ringed by shore deposits or strandlines, which were once emergent islands.  Compare - reworked lake plain.
The glacially-scoured, steep and arcuate side or wall of a cirque, dominated by rock-outcrops, rubble, and colluvium.  Compare - headwall.  SW & HD
The intersection of a specified plane of water with the beach; it migrates with changes of the tide or of the water level.  Compare  shore complex, barrier beach.
The inverted V-shaped end of a ridge that has been truncated or steeply beveled by steam erosion (e.g. meander scar or bluff), glacial truncation, or fault scarp displacement.   Compare - spur.  HP
The level or nearly level surface composing the land-ward part of a large delta; strictly, a flood plain characterized by repeated channel bifurcation and divergence, multiple distributary channels, and interdistributary flood basins.  GG
The lower portion of a canyon wall or escarpment marked by a sharp reduction in slope gradient from the precipitous cliff  above, and characteristically composed of thinly mantled colluvium (e.g. < 1 m) and / or carapaced with a thin surficial mantle of large rock fragments from above, which overly residuum of less resistant rock (e.g., shale) whose thin strata intermittently outcrop at the surface; a zone of erosion and transport common in the canyonlands of the semi-arid southwestern USA.  Compare - talus.  SW
The lowest, usually curved margin of displaced material of a landslide, most distant from the main scarp.  Commonly it has an irregular surface that has ripples and may be breached by radial cracks or gaps.  Compare - main scarp, minor scarp.  CV & SW
The most common type of sinkhole, caused by dissolution that forms fissures or a chimney and a depression in the bedrock surface which grows when closely spaced fissures underneath it enlarge and coalesce.  Compare - collapse sinkhole.  SW, WW, & GG
The most extensive landform on piedmont slopes, formed by (a) the lateral, downslope, coalescence of mountain-front alluvial fans into one generally smooth slope with or without the transverse undulations of the semi-conical alluvial fans, and (b) accretions of fan aprons.  FFP
The narrow strip of land immediately bordering any body of water, esp. the sea or a large lake; specifically the zone over which the ground is alternately exposed and covered by tides or waves, or the zone between high water and low water.  GG
The narrow strip of land in contact with or bordering a lake; especially the beach of a lake.  GG
The nearly level or slightly undulating central portion of a submerged, low-energy, depositional estuarine basin (McGinn, 1982) characterized by relatively deep water (1.0 to >2.5 m).  Compare  bay bottom.
The nearly level or slightly undulating central portion of a submerged, low-energy, depositional estuarine embayment characterized by relatively deep water (1.0 to >2.5 m).  Compare  lagoon bottom.
The nearly level or slightly undulating, relatively low-energy, depositional environment with relatively deep water (1.0 to >2.5 m) directly adjacent to an incoming stream and composed of interfingered and mixed fluvial and marine sediments (fluviomarine deposits).
The nearly level plain that borders a stream and is subject to inundation under flood-stage conditions unless protected artificially.  It is usually a constructional landform built of sediment deposited during overflow and lateral migration of the streams.  HP
The new and relatively short channel formed when a stream cuts through a narrow strip of land and thereby shortens the length of its channel.  GG
The part of a hillside or mountainside consisting of an outcrop of bare rock (scarp or cliff) that sheds colluvium to slopes below and commonly stands more steeply than the angle of repose of the colluvial slope (e.g. talus slope) immediately below. SW &  GG
The process, associated sediments (block glide deposit) or resultant landform characterized by a slow type of slide, in which largely intact units (blocks) of rock or soil slide downslope along a relatively planar surface, such as a bedding plane, without any significant distortion of the original mass.  Compare - rotational landslide, debris slide, lateral spread, landslide.  SW & DV
The process, associated sediments (creep deposit) or resultant landform or mantle characterized by a very slow type of earthflow dominated by the gradual movement of unconsolidated earthy material down slopes, driven primarily by gravity, but facilitated by saturation with water and by alternate freezing and thawing; sometimes redundantly called soil creep.  Compare - mudflow, flow, landslide, solifluction.
The process, associated sediments (debris avalanche deposit) or resultant landform characterized by a very rapid to extremely rapid type of flow dominated by the sudden downslope movement of incoherent, unsorted mixtures of soil and weathered bedrock which, although comparatively dry, behave much as a viscous fluid.  Compare - debris flow, rock fragment flow, debris avalanche, earthflow, landslide.  SW
The process, associated sediments (debris fall deposit) or resultant landform characterized by a rapid type of fall involving the relatively free, downslope movement or collapse of detached, unconsolidated material which falls freely through the air (lacks an underlying slip face); sediments have substantial proportions of both fine earth and coarse fragments; common along undercut stream banks.  Compare - rock fall, soil fall, landslide.  SW
The process, associated sediments (debris flow deposit) or resultant landform characterized by a very rapid type of flow dominated by a sudden, downslope movement of a mass of rock, soil, and mud (more than 50% of the particles are >2 mm), and whether saturated or comparatively dry, behaves much as a viscous fluid.  Compare - lahar, mudflow, landslide.  SW
The process, associated sediments (debris slide deposit) or resultant landform characterized by a rapid type of slide, composed of comparatively dry and largely unconsolidated earthy material which slides or rolls downslope (does not exhibit backward rotation) and resulting in an irregular, hummocky deposit somewhat resembling a moraine.  Compare - rotational landlside, block glide, lateral spread, landslide.  SW  & GG
The process, associated sediments (debris spread deposit) or resultant landforms characterized by a very rapid type of spread dominated by lateral movement in a soil and rock mass resulting from liquefaction or plastic flow of underlying materials that may be extruded out between intact units; sediments have substantial proportions of both fine earth and coarse fragments.  Compare - earth spread, rock spread, landslide.  SW & DV
The process, associated sediments (debris topple deposit) or resultant landform characterized by a localized, very rapid type of topple in which large blocks of soil and rock material literally fall over, rotating outward over a low pivot point;  sediments have substantial proportions of both fine earth and coarse fragments.  Portions of the original material may remain intact, although reoriented, within the resulting debris pile.  Compare - earth topple, rock topple, landslide.  SW
The process, associated sediments (earth spread deposit) or resultant landforms characterized by a very rapid type of spread dominated by lateral movement in a soil mass resulting from liquefaction or plastic flow of underlying materials that may be extruded out between intact units.  Compare - debris spread, rock spread, landslide.  SW & DV
The process, associated sediments (earth topple deposit) or resultant landform characterized by a localized, very rapid type of topple in which large blocks of soil material literally fall over, rotating outward over a low pivot point; sediments < 2 mm predominate.  Portions of the original material may remain intact, although reoriented, within the resulting deposit.  Compare - debris topple, rock topple, landslide.  SW
The process, associated sediments (earthflow deposit), or resultant landform characterized by slow to rapid flow dominated by downslope movement of a mass of rock, soil, and mud (more than 50% of the particles are < 2 mm), and whether saturated or comparatively dry, behaves much as a viscous fluid.  Compare - debris flow (coarse, less fluid), mudflow (more fluid), landslide.  SW
The process, associated sediments (mudflow deposit) or resultant landform characterized by a very rapid type of earthflow dominated by a sudden, downslope movement of a mass of rock, soil, and mud (more than 50% of the particles are < 2 mm), that behaves much as a viscous fluid when moving.  Compare - debris flow, flow, landslide.  SW
The process, associated sediments (rock spread deposit) or resultant landforms characterized by a very rapid type of spread dominated by lateral movement in a rock mass resulting from liquefaction or plastic flow of underlying materials that may be extruded out between intact units; rock bodies predominate.  Compare - debris spread, earth spread, landslide.  SW & DV
The process, associated sediments (rock topple deposit) or resultant landform characterized by a localized, very rapid type of fall in which large blocks of rock material literally fall over, rotating outward over a low pivot point; rock bodies predominate (little fine earth).  Portions of the original material may remain intact, although reoriented, within the resulting deposit.  Compare - earth topple, debris topple, landslide.  SW
The process, associated sediments (rockfall avalanche deposit) or resultant landform characterized by an extremely rapid, large type of rock-fragment flow (a type of landslide) which starts as a rockfall but turns into a flow and characteristically deposits rock-dominated debris long distances from the failure face (such as 10-20 times the fall height); occurs only when huge rockfalls and rockslides involving millions of metric tons of material attain extremely rapid speeds; most common in a rugged mountainous area; ex: the 1903 Franks, Alberta, Canada avalanche.  Sometimes loosely referred to as a long run-out landslide.  Compare - rock fragment flow, flow, landslide.  SW
The process, associated sediments (rockfall deposit) or resultant landform characterized by a very rapid type of fall dominated by downslope movement of detached rock bodies which fall freely through the air or by leaps and bounds (lacks an underlying slip face); also spelled rock fall. Compare - debris fall, soil fall,  landslide.  SW
The process, associated sediments (rotational debris slide deposit) or resultant landform characterized by an extremely slow to moderately rapid type of slide, composed of comparatively dry and largely unconsolidated earthy material, portions of which remain largely intact and in which movement occurs along a well-defined, concave shear surface and resulting in a backward rotation of the displaced mass; sediments have substantial proportions of both fine earth and coarse fragments.  The landform may be single, successive (repeated up and down slope), or multiple (as the number of slide components increase).  Compare - rotational earth slide, rotational rock slide, translational slide, lateral spread, landslide.  SW & DV
The process, associated sediments (rotational earth slide deposit) or resultant landform characterized by an extremely slow to moderately rapid type of slide, composed of comparatively dry and largely unconsolidated earthy material, portions of which remain largely intact and in which movement occurs along a well-defined, concave shear surface and resulting in a backward rotation of the displaced mass; sediments predominantly fine earth (< 2 mm).  The landform may be single, successive (repeated up and down slope), or multiple (as the number of slide components increase).  Compare - rotational debris slide, rotational rock slide, translational slide, lateral spread, landslide.  SW & DV
The process, associated sediments (rotational landslide deposit) or resultant landforms characterized by an extremely slow to moderately rapid type of slide, composed of comparatively dry and largely soil-rock materials, portions of which remain largely intact and in which movement occurs along a well-defined, concave shear surface and resulting in a backward rotation of the displaced mass.  The landform may be single, successive (repeated up and down slope), or multiple (as the number of slide components increase).  Compare - rotational debris slide, rotational earth slide, rotational rock slide, translational slide, lateral spread, landslide.  SW & DV
The process, associated sediments (rotational rock slide deposit) or resultant landform characterized by an extremely slow to moderately rapid type of slide, composed of comparatively dry and largely consolidated rock bodies, portions of which remain largely intact but reoriented, and in which movement occurs along a well-defined, concave shear surface and resulting in a backward rotation of the displaced mass.  The landform may be single, successive (repeated up and down slope), or multiple (as the number of slide components increase).  Compare - rotational debris slide, rotational earth slide, translational slide, lateral spread, landslide.  SW & DV
The process, associated sediments (soil fall deposit) or resultant landform characterized by a rapid type of fall involving the relatively free, downslope movement or collapse of detached, unconsolidated soil material which falls freely through the air (lacks an underlying slip face); sediments predominantly fine earth (< 2 mm); common along undercut stream banks.  Also called earth fall, and (not recommended) debris fall.  Compare - rock fall, debris fall, topple, landslide.  SW
The process, associated sediments (translational debris slide deposit) or resultant landform characterized by an extremely slow to moderately rapid type of slide, composed of comparatively dry and largely unconsolidated earthy material, portions or blocks of which remain largely intact and in which movement occurs along a well-defined, planar slip face roughly parallel to the ground surface and resulting in lateral displacement but no rotation of the displaced mass; sediments have substantial proportions of both fine earth and coarse fragments.  The landform may be single, successive (repeated up and down slope), or multiple (as the number of slide components increase).  Compare - translational earth slide, translational rock slide, rotational slide lateral spread, landslide.  SW & DV
The process, associated sediments (translational earth slide deposit) or resultant landform characterized by an extremely slow to moderately rapid type of slide, composed of comparatively dry and largely unconsolidated earthy material, portions or blocks of which remain largely intact and in which movement occurs along a well-defined, planar slip face roughly parallel to the ground surface and resulting in lateral displacement but no rotation of the displaced mass; sediments predominantly fine earth (< 2 mm).  The landform may be single, successive (repeated up and down slope), or multiple (as the number of slide components increase).  Compare - translational debris slide, translational rock slide, rotational slide, lateral spread, landslide.  SW & DV
The process, associated sediments (translational rock slide deposit) or resultant landform characterized by an extremely slow to moderately rapid type of slide, composed of comparatively dry and largely consolidated rock bodies, portions or blocks of which remain largely intact and in which movement occurs along a well-defined, planar slip face roughly parallel to the ground surface and resulting in lateral displacement but no rotation of the displaced mass; sediments predominantly fine earth (< 2 mm).  The landform may be single, successive (repeated up and down slope), or multiple (as the number of slide components increase).  Compare - translational debris slide, translational earth slide, rotational slide, lateral spread, landslide.  SW & DV
The process, associated sediments or resultant landform characterized by a mudflow composed chiefly of volcaniclastic materials on or near the flank of a volcano.  The debris carried in the flow includes pyroclastic material, blocks from primary lava flows, and epiclastic material.  Thick flows can exhibit a crude (poorly sorted) upward-fining sediment sequence.  Compare - mudflow.  SW & GG
The relatively flat surface, whether sand-free or sand-covered, between dunes;  GG
The relatively flat surface, whether sand-free or sand-covered, between dunes.  GG
The relatively flat, dominant component of the flood-tidal delta. At extreme low tide this landform may be exposed for a relatively short period (modified from Boothroyd et al., 1985).
The relatively steeper face of a cuesta, facing in a direction opposite to the dip of the strata.  Compare - dip slope.  GG
The sloping part of the beach that is alternately covered and uncovered by the uprush of waves, and where longshore movement of water occurs in a zigzag (upslope-downslope) manner.  Compare - shoreline.  GG
The sloping to near vertical surfaces between the canyon bottom and summits of bounding scarps that merge into adjacent uplands above.  Sideslopes are dominated by considerable rock outcrop and/or soils with bedrock within the soil profile.  Canyon walls commonly include cliffs or ledges of resistant rock, and may contain a more gently sloping beveled base cut into less resistant rocks (e.g. shale) near the bottom.  In large canyons (e.g. Grand Canyon), canyon walls may be vertically interrupted by the comparatively gentle slopes of canyon benches.  Note:  Scale, relief, and perspective may require use of closely related terms such as hillslope or mountain slope.  SW
The sloping to very steep surfaces between the valley floor and summits of adjacent uplands.  Well-defined, steep valley sides have been termed valley walls (not recommended).  Note:  Scale, relief, and perspective may require use of closely related terms such as hill slope or mountain slope.  HP
The small mound of debris sloughed from the root plate (ball) of a tipped-over tree.  Sometimes called a cradle knoll (not recommended).  Local soil horizons are commonly obliterated and result in heterogeneous strata.  Compare - tree-tip pit.  SW.  (Modified substantially from BHM).
The small pit or depression resulting from an area vacated by the root plate (ball) resulting from tree-tip ("tree-throw").  Such pits are commomly adjacent to small mounds composed of the displaced material.  Subsequent infilling commonly results in a heterogeneous soil matrix, that may or may not include a stone line that lines the depression.  Compare - tree-tip mound.  SW.  (Modified substantially from BHM).
The steep surface on undisturbed ground at the upper edge of a landslide, caused by movement of displaced material away from the undisturbed ground; it is visible a part of the surface of rupture (slip surface).  Compare - minor scarp, toe.  CV & SW
The steeply sloping surface on the lee side of a dune, standing at or near the angle of repose of loose sand, and advancing downwind by a succession of slides wherever that angle is exceeded.  GG
The submerged extension of an exposed (subaerial) point bar.
The term "meandering" should be restricted to loops with channel length more than 1.5 to 2 times the meander wave length.  Meandering stream channels commonly have cross sections with low width-to-depth ratios, cohesive (fine-grained) bank materials, and low gradient.  At a given bank-full discharge, meandering streams have gentler slopes, and deeper narrower, and more stable channel cross sections than braided streams.  Compare - meander, braided stream, flood-plain landforms.  HP & RR
The trace or track of a railroad route, commonly constructed slightly above the adjacent land, and composed mostly of earthy material (gravel, rock fragments, etc.).  Abandoned or reclaimed beds may no longer be topographically or visually distinct, but the materials used to construct them may still be a significant portion of the soil zone.  SW
The trace or track of a wheeled vehicle route that may or may not be raised slightly above the adjacent land, and may be composed mostly of earthy fill material (gravel, rock fragments, etc.) or local soil material.  Traffic can alter various soil properties primarily by compaction. Abandoned or reclaimed beds may no longer be topographically or visually distinct. However, materials used to construct beds or associated changes in soil properties may continue to have a significant impact upon soil management or plant growth.  SW
The upper or inner, usually dry, zone of the shore or beach, lying between the high-water line of mean spring tides and the upper limit of shore-zone processes; it is acted upon by waves or covered by water only during exceptionally severe storms or unusually high tides.  It is essentially horizontal or slopes gently landward, and is divided from the foreshore by the crest of the most seaward berm.  Compare - washover fan.  GG
The usually dry and nearly level lake plain that occupies the lowest parts of closed depressions, such as those occurring on intermontane basin floors.  Temporary flooding occurs primarily in response to precipitation-runoff events.  Playa deposits are fine grained and may or may not have high water table and saline conditions.  HP
The zone of smooth, laterally-coalescing, small alluvial fans that issue from gullies cut into the fan piedmont of a basin or that are coalescing extensions of the inset fans of the fan piedmont, and that merge with the basin floor at their toeslopes.  These are generally younger fans which onlap older fan surfaces.  FFP
The zone within which migration of a meandering channel occurs; the flood-plain area included between two imaginary lines drawn tangential to the outer bends of active channel loops.  Landform components of the meander-belt surface are produced by a combination of gradual (lateral and down-valley) migration of meander loops and avulsive channel shifts causing abrupt cut-offs of loop segments.  Landforms flanking the sinuous stream channel include:  point bars, abandoned meanders, meander scrolls, oxbow lakes, natural levees, and flood-plain splays.  Meander belts may not exhibit prominent natural levee or splay forms.  Flood plains of broad valleys may contain one or more abandoned meander belts in addition to the zone flanking the active stream channel.  HP
TheA mass of material torn away as a coherent unit during a landslide; a largely intact but displaced and commonly reoriented body of rock or soil.  SW & GG
use stream terrace.
Waterlogged, spongy ground containing alkaline decaying vegetation, characterized by reeds, that develops into peat.  It sometimes occurs in sinkholes of karst regions.  Compare - bog, marsh, swamp.  GG
Waterlogged, spongy ground, consisting primarily of mosses, containing acidic, decaying vegetation such as sphagnum, sedges, and heaths, that may develop into peat.  Compare - fen, marsh, swamp.  GG