CHAPTER X. 
QUATERNARY. 
HUANG-T’U FORMATION OF NORTHWESTERN CHINA. 
By BatLzy WILLIS. 
GENERAL DESCRIPTION. 
The term Huang-t’u, the name of the village of Huang-t’u-chai,* 
is used in this report for that extensive deposit of yellow earth hitherto 
called the Chinese Loess. In giving a local geographic name to a locally 
developed formation, we are following a well-established practice, but are 
also governed by the more cogent reason that the term ‘“‘Loess”’ should be 
limited in application to that peculiar material to which von Richthofen 
applied it. The translation of his definition follows: 
The loess of China is, like that of the Rhine, an earth of brown yellow color, so soft 
that one can easily rub it to pieces with the fingers, and yet at the same time so firm that in 
places where through erosion, as by running water, large masses are broken off, it remains 
standing in perfectly vertical walls several hundred feet high. * * * It is so fine an earth 
that one can rub most of it into the pores of the skin; nothing then remains but some fine 
grains of sand, of which there are sometimes more, sometimes less. It is one of the most 
characteristic marks of the loess that these are angular, not rounded. By repeated washing 
with water, one can separate this from a much greater mass of material that may be called 
clay and is tinted brownish-yellow by iron. A third important element is carbonate of 
lime, which one may distinguish with the naked eye and which can be shown to be present 
by the use of acid. 
** * * * * * * * * 
On every bit of loess, even the smallest, one may recognize a certain texture, which 
consists in that the earth is traversed by long-drawn-out tubes, which are in part extra- 
ordinarily fine and in part somewhat coarser; which branch downward after the manner 
of fine rootlets and generally are coated with a thin white crust of carbonate of lime. If 
one examines the loess in place one sees that most of these little channels are nearly vertical, 
yet branch at an acute angle and downwards, whereby an incomplete parallel structure is 
maintained. If one is looking at a loose piece, but not exactly at the surface of parallel 
fracture, one sees the ends of the little tubes which occasion an appearance of minute 
*Huang-t’u-chai, Yellow Earth Village, in the province of Shan-si, lat. 38°, long. 112° 40’, atlas 
sheet B II. 
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