280 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1926 
by Doctor Zdansky and himself. Doctor Anderson’s conclusions are 
embodied in the Geological Survey’s memoir on the Cenozoic of 
North China (1-121). 
No attempt seems to have been made recently to bring together 
more than one aspect of our present knowledge. Such an attempt 
may now serve to unify the results so far gained, and act as a basis 
for later more complete scientific study. A summary of this kind does 
not aim at being exhaustive, and avoids more than passing reference 
to disputed points which are discussed elsewhere. At the same time, 
in this instance it is possible to add also certain field and laboratory 
observations recorded here for the first time. Prof. E. O. Wilson of 
Yenching University, Prof. T. New of Tsinghua College, and Prof. 
W. ©. Lowdermilk of the University of Nanking, have placed at my 
disposal the results of researches they have carried out, in each case 
making valuable contributions which fill important gaps in our pre- 
vious knowledge. I am glad of this opportunity to express my ap- 
preciation of their generous cooperation. 
DISTRIBUTION OF LOESS IN GENERAL 
Loess is an important fine-grained loam formation, widespread in 
various parts of the Northern Hemisphere. Its uncompacted nature 
won the name “ loess” in the German Rhineland, where it forms a 
soil of high fertility. It is widely developed in a farm-land belt that 
stretches across northeast France and Belgium and extends irregu- 
larly into Poland, Czechoslovakia, and Rumania. In the United 
States it covers large parts of Ohio, Indiana, [llinois, Lowa, Kansas, 
and Nebraska, with a long southern projection through Missouri 
down the east bank of the Mississippi. 
Even in Asia, China has no monopoly of the loess. According to 
v. Tillo (4-566) loess covers 511,150 square miles, or 3 per cent of the 
continent. Assuming an average depth of 30 meters, Walther has 
calculated that this represents a volume of 40,000 cubic kilometers of 
material, almost all produced by rock decay in arid regions (11-193). 
Sven Hedin and other travelers report it from places in the interior. 
THE LOESS OF CHINA 
In China loess is strongly developed throughout the basin of the 
Yellow River and at other places in Chihli, Shansi, Shensi, Honan, 
Kansu, and Shantung. Small accumulations are reported from An- 
hui, Kiangsu, and elsewhere. 
It should be said at the outset that in the case of the Chinese loess 
the term has been used to include other deposits which, though some- 
what similar in appearance, differ vastly both in age, composition, 
character, and mode of origin from genuine loess. This confusion 
has given rise to the very exaggerated estimates of its thickness re- 
