256 black. PERMAFROST [Ch. 14 



places, bedrock is disintegrated, reduced in size, thoroughly mixed, 

 and rapidly transported, the result being a silt-sized sediment that is 

 widespread in the Arctic. Disagreement exists among various authors 

 (Bryan, 1949; Hopkins, 1949; P. S. Smith, unpublished manuscript; 

 Zeuner, 1945; Taber, 1943a; Tuck, 1940) whether some of the material 

 is derived from eolian, lacustrine, or local frost-splitting and mass- 

 wasting processes. Size-distribution curves, mineral comparisons, 

 chemical analyses, comparisons with glacial materials and with or- 

 ganic materials, etc., have been used by various investigators to prove 

 their point, but the differences of opinions have by no means been re- 

 solved. 



Frost action (frost-heaving, frost-stirring, and frost-splitting) and 

 gravity movements result in many surface forms that are found most 

 abundantly in areas of permafrost: strukturboden, involutions, frost 

 boils, hummocks, applanation terraces, terrecettes, and soil stripes 

 (Judson, 1949; Richmond, 1949; Schafer, 1949; Smith, 1949; Cailleux, 

 1948; Troll, 1948, 1947, 1944; Washburn, 1947; Conrad, 1946; Zeuner, 

 1945; Taber, 1943a; Sharp, 1942b; Gatty et al, 1942; Steche, 1933; 

 Hogbom, 1914). Annual freezing in permafrost areas also forces 

 changes in surface and ground-water migration and commonly results 

 in pingos, frost blisters, ice mounds, icings, aufeis, and other related 

 forms (Muller, 1945; Troll, 1944; Sharp, 1942a; Mullis, 1930). Many 

 of the forms produced by frost action and seasonal freezing are closely 

 related in character and origin; however, the lack of a standardized 

 terminology for these features produces a perplexing picture. 



Little can be said quantitatively regarding the importance of frost 

 action (and indirectly permafrost) in past sediments and soils (Zeu- 

 ner, 1945). Throughout the world, fossil deposits of former glaciers 

 have been found in the stratigraphic column. They indicate many 

 periods of glaciation and, hence, cold climates. Undoubtedly perma- 

 frost was present during those times. Fossil forms derived from frost 

 and permafrost are known (Horberg, 1949; Judson, 1949; Richmond, 

 1949; Schafer, 1949; H. T. U. Smith, 1949b; Wahrhaftig, 1949; Zeuner, 

 1946, 1945; Troll, 1944), and they provide data on the processes pro- 

 ducing the surficial materials and the environment of deposition. 

 These features are only now being recognized and studied in the detail 

 that is warranted (Bryan, 1949). 



Permafrost throughout the world has provided an outstanding 

 wealth of material for paleontologists and archeologists. In peren- 

 nially frozen Alaskan placers alone, investigators have found more 

 than 27 different plants (Chaney and Mason, 1936), including whole 

 forests of buried stumps (Giddings, 1938) ; numerous iron and other 



