Review of Recent Geological Literature. 
259. 
As to the specific identification, the following have been ex- 
pressly identified: Mastodon, Elephas primigenius and Elephas 
americanus, the first mentioned probably being Mastodon ameri- 
canus, of which 39 individuals are listed. 
The relations these fossils bear to the different parts of the 
drift sheet as more recently subdivided by the Iowa geologists is 
plainly one of great interest. Many of the observations were made 
before the different parts of the drift had been recognized, "and 
some were even made by geologists who did not regard land ice as 
necessarily an agent in the deposition of the glacial till." Barring 
all the uncertainties and imperfections of the record of the data 
discussed the author still reaches some valuable and interesting 
conclusions. These conclusions are tabulated below. 
AGE 
>> 
X to 
11 - 
h5 
z s 
£ w ■«' 
.ax 
in -w m 
Specimens of unknown age. 
Mammoth 
9 
2 
7 
13 
2 
1 
1 
4 
1 
2 
2 
1 
1 
2 
1 
1 
Elephas primigenius 
Elephant . 
Mastodon 
Specimens of the pre-Kansan (?) or Kansan 
(?) age. 
Mastodon . 
Specimens from the ferretto zone, po>st-Kan- 
san and pre-loessian. 
1 Mastodon 
Specimens from the surface of the Illinoian 
drift, post-Illinoian and pre-loessian. 
Undetermined 
1 
Specimens from the base of the loess, post- 
Kansan and pre-Iowan. 
Elephant 
Mammoth 
Mastodon 

1 
Undetermined 
Specimens from the loess. 
Elephas americanus 
Mammoth 
Undetermined 
From the area of the Iowan drift, post-Iowan. 
Mammoth 
Mastodon 
1 
