802 We, (C, (CSaVAN ML ILILION 
by some of my colleagues and by myself to find criteria of dis- 
crimination between aqueous and eolian loess. While individual 
types of both deposits are not difficult to find, a criterion or a 
series of criteria of general applicability which shall distinguish 
the two and assign to each its appropriate part is yet wanting. 
Richtofen in his classic work on China urged as the explana- 
tion of the great Chinese loess an eolian hypothesis supple- 
mented by a fluvio-lacustrine hypothesis. He insisted that the 
original and chief loess deposits were formed by dust blown 
from the great arid plateaus and lodged on the more fertile plains 
of China, and that from these primary deposits the streams 
gathered and subsequently redeposited in fluvial or lacustrine 
form a subordinate portion, thus giving origin to a secondary 
loess formation. Going beyond that field he and his supporters 
have apparently tried to apply this secondary factor to the 
explanation of difficulties in the European and American loess, 
to which its application is more than doubtful. It is interesting, 
however, to note that the loess puzzle of China, even in the mind 
of its chief exponent, finds a full solution only in a combination 
of eolian and aqueous hypotheses. The present writer herein 
urges the trial of a similar combination of hypotheses, but 
reverses the order of the terms in their Mississippian applica- 
tion. The aqueous loess is made primitive and the eolian loess 
secondary. The Richtofen loess may be said to be first eolian 
and secondarily aqueous; the Mississippian loess, first aqueous, 
and secondarily eolian. The Richtofen loess in its ultimate 
origin is residuary. The Mississippian loess, in its ultimate 
origin, is glacial. The Richtofen mode of origin may be said 
to be eolio-fluvial, the mode herein advocated, fluvio-eolian, in 
which terms the order of the words indicates the order of deri- 
vation and each word signifies a variety of loess. 
T. C. CHAMBERLIN. 
