height, buttes are transitional to mesas. (See plateau 

 and cuesta.) HP 

 Bypassed — The situation of a fan or pediment surface 

 that once had sediment spread across it by ephemeral 

 washes, but that is now protected from surficial stream 

 erosion or alluviation because the drainageways cross- 

 ing it are not incised. FFP 



Caldera — A large, basin shaped, volcanic depression, 

 more or less circular or cirquelike in form, the diameter 

 of which is many times greater than that of the included 

 volcanic vent or vents, regardless of the steepness of 

 the walls or the form of the floor. Three major types — 

 explosion, collapse, erosion. GG 



Caliche — A general term for a prominent zone of second- 

 ary carbonate accumulation in surficial materials of 

 warm, subhumid to arid areas formed by both geologic 

 and pedologic processes. Finely crystalline calcium car- 

 bonate forms a nearly continuous surface-coating and 

 void-filling medium in geologic (parent) materials. Ce- 

 mentation ranges from weak in nonindurated forms to 

 very strong in types that are indurated. Other minerals 

 (carbonate, silicate, sulphate) may be present as acces- 

 sory cements. Most petrocalcic and some calcic hori- 

 zons are caliche. HP 



Canyon — A long, deep, narrow, very steep-sided valley 

 with high and precipitous walls in an area of high local 

 relief (for example, mountain or high plateau terrain). 

 HP 



Carolina bay — Any of various shallow, often oval or 

 elliptical, generally marshy, closed depressions in the 

 Atlantic coastal plain (from southern New Jersey to 

 NE Florida, especially developed in the Carolinas). 

 They range from about 100 m to many kilometers in 

 length, are rich in humus, and contain trees and shrubs 

 different from those of the surrounding areas. GG 



Catsetps— (See terracettes.) 



Channel — 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 dumps of cobbles and 

 stones. Channels, excepting flood plain playas, are 

 landform elements. FFP 



Cirque — Semicircular, concave, bowl-like areas with 

 steep faces primarily resulting from erosive activity of 

 a mountain glacier, (fig. B-6) HP & GG 



Clast — An individual constituent, grain, or fragment of 

 sediment or rock, produced by the mechanical weath- 

 ering (disintegration) of a larger rock mass. HP 



Clastic — Pertaining to a rock or sediment composed 

 mainly of fragments derived from preexisting rocks or 

 minerals and moved from their place of origin. (See 

 detritus, epiclastic, and pyroclastic.) HP 



Cliff— Any high, very steep, to perpendicular or over- 

 hanging face of a rock; a precipice. GG 



Coalescent fan piedmont — (See bajada.) HP 



Coastal plain— Any plain or plains of unconsolidated 

 fluvial or marine sediment which had its margin on the 

 shore of a large body of water, particularly the sea (for 

 example, the coastal plain of SE United States extend- 

 ing for 3,000 miles from New Jersey to Texas). GG 



Col — A narrow, sharp-edged pass or saddle-like depres- 

 sion in a mountain range between two adjacent peaks; 

 especially a deep pass formed by the headward erosion 

 and intersection of two cirques. Also, the highest point 

 on a divide between two valleys. GG 



Colluvial — Pertaining to material transported and depos- 

 ited by mass wasting (direct gravitational action) and 

 local unconcentrated runoff on and at the base of steep 

 slopes. HP 



Colluvium — Unconsolidated earth material deposited on 

 and at the base of steep slopes by mass wasting (direct 

 gravitational action) and local unconcentrated runoff. 

 HP 



Conglomerate — A coarse-grained, clastic rock composed 

 of rounded to subangular rock fragments, (larger than 

 2 mm) commonly with a matrix of sand and finer mate- 

 rial; cements include silica, calcium carbonate, and 

 iron oxides. The consolidated equivalent of gravel. 

 (See breccia.) HP 



Constructional (geomorphology) — Owing its origin, form, 

 position, or general character to depositional (aggrada- 

 tional) processes, such as accumulation of sediment to 

 form an alluvial fan or terrace. (See erosional.) HP 



Creep — Slow mass movement of earth material down 

 relatively steep slopes, primarily under influence of 

 gravity but facilitated by water saturation and frost 

 action. HP 



Crest — The commonly linear top of a ridge, hill, moun- 

 tain, and the like. (See summit.) FFP 



Cryoplanation — Reduction of land surfaces by processes 

 associated with frost action. DGT 



Cuesta — An asymmetric, homoclinal ridge capped by 

 resistant rock layers of slight to moderate dip (< 10°, 

 < 16%); produced by differential erosion of interbed- 

 ded resistant and weak rocks. A long, gently sloping to 

 sloping face (dipslope), roughly paralleling the inclined 

 beds; opposes a relatively short and steep (scarp) face 

 cut across the tilted rocks. (See hogback and mesa.) HP 



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