366 The American Geologist. December, 1903. 
presented ideal conditions for such mingling of sand and dust. 
It is here that his hybrid "drift-loess" was formed. There is 
no connection, as far as known, between this "drift-loess" and 
Calvin's "flooded valley deposits" which are referred to the 
"drift-loess" by Winchell.* 
The occurrence of real till in loess, excepting where slip- 
ping' may account for its presence, has not yet been demonstrat- 
ed. Even Bain's example, f is not conclusive. He says that 
the exposure of till to which he refers is "about 150 feet above 
the river, and the till is above any similar deposit known to 
occur in this vicinity." Anyone who is familiar with the topo- 
graph) and altitudes of the part of Woodbury county referred 
to, will lie very slow to make unquestioned application of Bain's 
careful statement concerning a point only 150 feet above the 
river. In any case the extreme rarity of such cases should lead 
to great caution. Loess and drift are not so intermingled as to 
warrant sweeping conclusions concerning genetic relationship. 
The fineness and homogeneity of the loess, together with 
the presence of numerous terrestrial fossils which required 
abundant vegetation for their maintenance, are sufficient to 
show that the loess was not deposited by ice. If it is maintain- 
ed that the loess was deposited by flooded streams after 
the ice receded, then it devolves upon the advocates of this 
theory to explain the following phenomena: 
a. The region immediately adjacent to the larger streams 
in our loess-covered sections is the highest, as a rule, and has 
the thickest deposit of loess. There are no bluffs or elevations 
lying beyond, which could have formed the hanks of the swol- 
len streams. If there were great harriers southward which re- 
tained the vast volumes of water postulated by this supposition 
where are traces of them ? 
b. The loess is fine and comparatively homogeneous. The 
movement of such enormous volumes of watei would certainlv 
have resulted in the transportation of more coarse material. 
c. The loess is usually of approximately uniform thickness 
on tops and slopes of hills, and is often laminated parallel to the 
surface. Under what conditions could flooded streams have pro- 
duced this result? If it is assumed that the loess was deposited 
•Am Gi;<>i... 1. c. p. 279. 
fCited by Winchbll, Am. Gbol., 1. c. p. 281. 
