706 The Chinese Loess Puzzle. [ December, 
portion. The most striking facts with regard to this material in 
China are its wide-spread distribution and its enormous thick- 
ness, — facts which, taken in connection with its composition and 
structure, render its origin one of the most perplexing of geo- 
logical problems. 
First, as toits distribution. According to Richthofen, this for- 
mation is spread over a large part of the region drained by the 
Hwang-Ho or Yellow River, — a name derived from the color of 
the material which this great stream is continually carrying in 
suspension towards the Yellow Sea, in which name we again rec- 
ognize the coloration given by the particles of the loess, which 
itself is called by the Chinese hwang-tu or yellow earth. For 
nearly a thousand miles from the borders of the great alluvial 
plain of Pechele, through the provinces of Shansi, Shensi, and 
Kansu, everywhere to the north of the Wei, which runs along 
the northern base of the range of the Tsing-ling-shan, the loess 
may be followed up to the very divide which separates the basin 
of the Hwang-Ho from the region destitute of drainage into the 
sea. Towards the north, it reaches almost to the edge of the 
Mongolian plateau. Furthermore, it may be observed in the 
province of Honan, along the south side of the most easterly 
outliers of the Kwenlun, filling a large portion of the middle part 
of the basin of the Han, covering large areas in Shantung, and 
reaching southwards in isolated patches as far as the Yangtse. 
The area over which the loess spreads itself almost continuously 
is as large as the whole of Germany ; while it is found in more or 
less detached portions over an additional area nearly half as large 
as that empire. 
From the known topographical character of the loess-covered 
region, it will be recognized at once that the formation in ques- 
tion oceurs at very varying altitudes, or that it is distributed 
without regard to the elevation of the surface on which it rests. 
From near the level of the sea up to six thousand feet and more 
above it, this characteristic material lies, covering valley and 
mountain slope, absent only on the crests of some of the higher : 
dividing ridges, This extraordinary range of vertical position 
has not been given to the loess by changes of level of the land 
since it was deposited, for Richthofen declares that it clearly re- 
sults from his researches that the relative position of the higher he 
and lower portions of the region in question has not been changed 
since the deposition of the loess; although he believes that, a8 
a whole, its eastern border has been depressed in altitude, the — : 
