EEE 
Geology and Natural History. 67 
Pliohippus and Hipparion of the Pliocene, to the recent Zyuus, 
In other groups of mammals, likewise, so far as observed, the 
size of the brain shows a corresponding increase in the succes- 
sive subdivisions of the Tertiary. These facts have a very im- 
portant bearing on the evolution of mammals, and open an inter- 
esting field for further investigation. . 
al (or Lignite) in the Cretaceous of Minnesota,—Prof. N. 
R 
2. 
H. Winchell, in his Report for 1873, announces the existence of 
sometimes into good Cannel coal, or into a bituminous clay; the 
compact Cannel coal is in detached lumps, and occurs throughout 
a band about four feet in thickness. At another outcrop, the Lig- 
corps of Professor H. D, Rogers on the former surve 
the text, which the new facts and the progress in the principles of 
the science required, the author has introduced a c apter 
of water and the atmosphere, an E 
close, presenting a brief review of geological dynamics, under the 
title of “Effects referred to their causes.” The work is printed 
in excellent style; and although containing one-sixth more matter _ 
than the former edition, the volume, owing to its larger page of 
ual size. 
