LOESS OF CHINA——BARBOUR 281 
corded by many observers. Von Richthofen gives figures of 500, 
600 and even 1,500 feet, and one reads travelers’ references to “ hun- 
dreds of feet of loess.” But it is doubtful if there exist outside of 
Kansu deposits of much more than 200 feet thickness, the deeper 
deposits proving almost invariably to include the underlying Hip- 
parion clay, or more recent gravels, silt, and “ redeposited loess.” 
Andersson (1-123) gives 60 meters as the maximum thickness of true 
undoubted loess observed in any place.* 
A second cause for such overestimates is the failure to realize that 
loess was spread by wind over a valley-dissected land surface. Hence, 
though often found at considerable altitudes, it may have no 
greater vertical depth there than it does on the lower valley slopes, 
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just as the people in the back rows of an amphitheater are under no 
obligation to be taller than those in the front seats. 
The true Chinese loess is a yellow-gray poorly consolidated loam 
deposit of the fineness of silt, which shows a characteristic absence 
of horizontal layer structure, being essentially nonstratified, and a 
tendency to split along roughly vertical joint planes, so as to form 
perpendicular cliffs and walls. No attempt is made here to describe 
the remarkable erosion features, natural arches, crevasses, pinnacles, 
sinks, etc., common- in loess regions. These are well described in 
such articles as those of Fuller (8-570) and Sowerby (2). (See 
pls. 1-6.) 
For the most part it is nonfossiliferous, the only animal remains 
found in any quantity being the shells of small nonmarine snails 
8In conversation Doctor Andersson has mentioned that recent careful observations in 
Kansu have showed that in one or two places this maximum ought to be increased by some 
20 or more meters. Dr. George G. Cressey has measured cliffs over 300 feet high near 
Sui-te-chow on the west bank of the Yellow River in Shensi. Even greater thicknesses may 
exist in a few restricted localities. 
