is usually plane and often occurs with parallel joints to 

 form part of a joint set. HP 



Kame — A moundlike hill of ice-contact glacial drift, 

 composed chiefly of stratified sand and gravel. HP 



Kame terrace — A terrace-like ridge consisting of stratified 

 sand and gravel (1) deposited by a meltwater stream 

 flowing between a melting glacier and a higher valley 

 wall or lateral moraine, and (2) left standing after the 

 disappearance of the ice. It is commonly pitted with 

 "kettles" and has an irregular ice-contact slope. HP 



Karst — A type of topography that is characterized by 

 closed depressions or sink holes, and is dependent 

 upon underground solution and the diversion of sur- 

 face waters to underground routes. It is formed over 

 limestone, dolomite, gypsum, and other soluble rocks 

 as a result of differential solution of these materials 

 and associated processes of subsurface drainage, cave 

 formation, subsidence, and collapse. HP 



Kettle — A steep-sided bowl-shaped depression without 

 surface drainage in glacial drift deposits and believed 

 to have formed by the melting of a large, detached 

 block of stagnant ice buried in the glacial drift. HP 



Knickpoint — Any interruption or break in slope; a point 

 of abrupt inflection in the longitudinal profile of a 

 stream or of its valley. HP 



Knob — (a) A rounded eminence, as a knoll, hillock, or 

 small hill or mountain; especially a prominent or iso- 

 lated hill with steep sides, commonly found in the 

 southern U.S. (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 



Knoll — A small, low, rounded hill rising above adjacent 

 landforms. (Synonyms for knoll are hillock and knob.) 

 HP 



Lacustrine deposit — Clastic sediments and chemical pre- 

 cipitates originally deposited in lakes and exposed 

 when the water level is lowered or the elevation of the 

 land is raised. HP 



Lagoon — A shallow stretch of water partly or completely 

 separated from a sea or lake by an offshore reef, bar- 

 rier island, sandbank or spit. GG 



Lahar — A mudflow composed chiefly of volcaniclastic 

 materials on the flank of a volcano. The debris carried 

 in the flow includes pyroclastic material, blocks from 

 primary lava flows, and epiclastic material. HP 



Lake plain — A nearly level surface marking the floor of 

 an extinct lake filled in by well-sorted, fine textured, 

 stratified sediments. GG 



Lamination (lamina) — A sedimentary layer less than 1 cm 

 thick. HP 



Landform — Any physical, recognizable form or feature 

 of the earth's surface, having a characteristic shape, 

 and produced by natural causes; it includes major 

 forms such as a plain, plateau, or mountain, and minor 

 forms such as a hill, valley, slope, esker, or dune. Taken 

 together, the landforms make up the surface configu- 

 ration of the earth. The "landform" concept involves 

 both empirical description of a terrain (land-surface 

 form) class and interpretation of genetic factors ("nat- 

 ural causes"). HP 



Landform element — A morphological part of a compo- 

 nent landform. Hillslope landform elements may be 

 divided into slope components. FFP 



Landscape — (General) all the natural features, such as 

 fields, hills, forests, and water that distinguish one part 

 of the earth's surface from another part; usually that 

 portion of land which the eye can comprehend in a 

 single view, including all of its natural characteristics. 

 (Geology) The distinct association of landforms, espe- 

 cially as modified by geologic forces, that can be seen 

 in a single view. HP 



Landslide — A mass-wasting process, and the landform 

 produced, involving moderately rapid to rapid (greater 

 than 1 ft per year) downslope transport, by means of 

 gravitational stresses, of a mass of rock and regolith 

 that may or may not be water saturated. HP 



Land-surface form — The description of a given terrain 

 unit based on empirical analysis of the land surface 

 rather than interpretation of genetic factors. Surface 

 form may be expressed quantitatively in terms of ver- 

 tical and planimetric slope-class distribution, local and 

 absolute relief, and patterns of terrain features such as 

 interfluve crests, drainage lines, or escarpments. HP 



Ledge — 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 of softer 

 rocks. A rocky outcrop; solid rock. An underwater 

 ridge of rocks, especially near the shore; also a near 

 shore reef. A quarry exposure or natural outcrop of a 

 mineral deposit. GG 



Levee (streams) — An artificial or natural embankment 

 built along the margin of a watercourse or an arm of 

 the sea, to protect land from inundation or that con- 

 fines streamflow to its channel. A synonym for levee is 

 earth dike. GG 



Limestone — A sedimentary rock consisting chiefly (more 

 than 50%) of calcium carbonate, primarily in the form 

 of calcite. Limestones are usually formed by a combi- 



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