248 black. PERMAFROST [Ch. 14 



ica (Tremayne, 1948) is currently making an annotated bibliography 

 of all arctic literature, including permafrost. A list of 190 titles of 

 Russian articles dealing with permafrost is given by Weinberg (1940). 



The multitude of problems associated with frost action, as we refer 

 to it in the United States, appropriately should accompany any dis- 

 cussion of permafrost. However, limitation on space permits only 

 a passing reference to the relationship of permafrost to frost action. 

 An annotated bibliography on frost action has been prepared by the 

 Highway Research Board (1948). 



Thanks are due Lewis L. Ray, P. S. Smith, Inna V. Poire, Troy L. 

 Pewe, David M. Hopkins, William S. Benninghoff, Joel H. Swartz, and 

 D. J. Cederstrom, of the U. S. Geological Survey, and to Stephen Taber 

 and Kirk Bryan for critical reading of this manuscript. These and 

 others in the Geological Survey have provided many valuable sug- 

 gestions for which individual acknowledgment is difficult. The use of 

 unpublished manuscripts and notes of P. S. Smith and C. V. Theis is 

 greatly appreciated. 



PERMAFROST 



The term permafrost was proposed and defined by Muller (1945). 

 A longer but more correct English phrase is "perennially frozen 

 ground" (Taber, 1943a). The difficulties of the present terminology 

 are discussed by Bryan (1946a, b), who proposed a new set of terms. 

 These are discussed by representative geologists and engineers (Bryan, 

 1948). Such terms as cryopedology, congeliturbation, congelifraction, 

 and cryoplanation are being accepted by some geologists (Judson, 

 1949; Denny and Sticht, unpublished manuscript; Cailleux, 1948; 

 Troll, 1948) in order to attempt standardization of the terms regard- 

 ing perennially frozen ground and frost action. The term perma- 

 frost has been widely adopted by agencies of the United States Gov- 

 ernment, by private organizations, and by scientists and laymen alike. 

 Its use is continued in this chapter because it is simple, euphonious, 

 and easily understood by all. 



Extent 



Much of northern Asia and northern North America contains peren- 

 nially frozen ground (Fig. 1) (Sumgin, 1947; Muller, 1945; Obruchev, 

 1945; Troll, 1944; Taber, 1943a; Cressey, 1939). 



The areal subdivision of permafrost into continuous, discontinuous, 

 and sporadic bodies is already possible on a small scale for much of 



