ZOOLOGY. 



389 



and lakes of brackish and fresh water, whose deposits form the bed of 

 the Laramie epoch." Of the four principal horizons of Europe, (1) the 

 Urgaptian is not at all represented, so far as known, in S'orth America ; 

 (2) the Gault in its upper portion and the Cenomanian in its lower por- 

 tion are to some extent represented by the Dakota, but (3) the greater 

 portion of Cenomanian is equivalent to the Colorado} and (4) the Seno- 

 nian is paralleled very well indeed by the Fox Hills group. 



The name Post-cretaceous is given by Cope to (1) the Laramie, which 

 has a very characteristic fauna and is not represented in Europe, and 

 the (2) Puerco, which is perhaps represented by the Thanetian of that 

 continent. 



The Tertiary epoch is abundantly developed, and from its base upwards 

 the strata contain remains of numerous mammalian types. The i^aral- 

 lelism supposed to exist between the various beds of the iSTorth Ameri- 

 can continent and Europe are exhibited in the following table derived 

 from Professor Cope's article : 



The deductions Professor Cope has drawn from his examination of 

 the various questions involved in these identifications are that (1) "por- 

 tions of all the faunae of all the primary divisions of geologic time have 

 been recognized on both the Eui'opean and North American continents " ; 

 (2) these are mostly represented in an inexact manner, as the Coal meas- 



