260 
The American Geologist. 
October, 1905 
AGE 
From the area of the Wisconsin drift, post- 
Wisconsin. 
Elephas priraigenius 
Elephant 
Mammoth 
Mastodon 
Undetermined 
From alluvium, mostly sub-recent, but some, 
perhaps, older. 
Elephas primigenius 
Mammoth 
Mastodon 
Undetermined 
- > = 
o . . 
Bio 
1 
2 
10 
4 
Associated with these mastodon and mammoth fossils have 
been found also the bones of the buffalo, wolf, peccary deer and 
elk; also the "land shells Helicina, Succinea, Pryamidula. Bifidaria, 
Limnaea and others which are characteristic of the loess." "In Rock 
Island the loess which contained elephant bones also contained 
fragments of coniferous wood, and at Davenport, in Iowa, the peaty 
loess from which tusks and other bones were taken has a seam 
of diatomaceous earth, in which no less than thirty-three now 
living species of diatoms have been identified." 
The discovery of these land mammal fossils in the loess which 
contains the land shells so often repealed to by those who adopt 
the aeolian theory of the origin of the loess in the Mississippi val- 
ley, adds so much more of the same kind of evidence to the sup- 
port of that theory. It is only necessary to assume that the wind 
storms thai buried the land shells in wind-blown dust and sand 
were, say, ten thousand times more violent and dust-laden than 
has been supposed, and that the great land animals that co- 
existed with the snails were overwhelmed at the same time. And, 
further, the winds must have been violent enough to rend apart 
their carcases and to scatter the bones of their skeletons for con- 
siderable distances asunder, even extracting the teeth from their 
sockets. It is a much more natural and simple matter to get the 
wind-blown dust and the laminated loess into superposition above 
these fossils than to get the fossils below considerable thicknesses 
of the laminated loess. The seolian hypothesis accomplishes this in 
a most admirable and satisfactory manner. 
From the foregoing table it is learned that .the mastodon and 
the mammoth existed, perhaps, prior to the Kansan ice epoch, and 
continued into the Iowan epoch, into the Wisconsin and even into 
