[Reprinted from Tue AmERIoAN Naturauist for February, 1877.] 
THE SUESSONIAN FAUNA IN NORTH AMERICA. 
BY PROF. E. D. COPE. 
(* a paper read before the National Academy of Sciences at the 
spring session of 1876 in Washington, the writer announced 
the identification of the Wahsatch Eocene formation of New 
Mexico with the Suessonian or Lower Eocene of France and 
England. The beds, which were explored while connected with 
the United States Geographical and Geological Survey, west of 
the one hundredth meridian, in charge of Lieut. G. M. Wheeler, 
in 1874, were found to contain the remains of a fauna, almost 
identical with that of the European beds in question. This was 
thought to be an important accession to American geology, as 
furnishing a basis for an estimation of the relative ages of the 
formations immediately above and below the Wahsatch horizon. 
The parallelism of the fauna includes the genera of reptiles, birds, 
