﻿XXXV111 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



nation as our ignorance of most of the insects and all the pulmo- 

 niferous mollusca, as well as of Helices and other land shells of the 

 same era. 



Eighthly, the fish and reptiles of the secondary rocks are as fully 

 developed in their organization as those now living. The birds are 

 represented by numerous foot-prints and coprolites in the Trias of 

 New England, and by a few bones not yet generically determined, 

 from Stonesfield and the English Wealden. 



Ninthly, the land quadrupeds of the secondary period are limited 

 to two genera, occurring in the inferior oolite of Stonesfield ; 

 the cetacea by one specimen from the Kimmeridge clay, the true 

 position of which requires further inquiry, while an indication of 

 another is afforded by a cetacean parasite in the chalk. But we 

 have yet to learn whether in the secondary periods there was really 

 a scarcity of mammalia, (such as may have arisen from an extraor- 

 dinary predominance of reptiles, aquatic and terrestrial, discharging 

 the same functions,) or whether it be simply apparent and referable 

 to the small progress made as yet in collecting the remains of the 

 inhabitants of the land and rivers, since we have hitherto discovered 

 but few freshwater, and no land mollusca in rocks of the same age. 



Tenthly, in regard to the palaeontology of the tertiary periods, 

 there seems every reason to believe that the orders of the mammalia 

 were as well represented as now, and by species as highly organized ; 

 whether we turn to the Lower, or to the Middle, or to the Upper 

 Eocene periods, or to the Miocene or Pliocene ; so that during five or 

 more changes, in this the highest class of vertebrata, not a single 

 step was made in advance, tending to fill up the chasm which sepa- 

 rates the most highly gifted of the inferior animals and man. 



Eleventhly, the geological proofs that the human species was cre- 

 ated after the zoological changes above enumerated are very strong. 

 It even appears that man came later upon the earth than the larger 

 proportion of the animals and plants which are now his contempo- 

 raries. Yet, for reasons above stated, had the date of his origin 

 been earlier by several periods, the event would have constituted 

 neither a greater nor a less innovation, on the previously established 

 state of the animate world. In other words, there are no palaeonto- 

 logical grounds for believing that the mammiferous fauna after being 

 slowly developed for ages had just reached its culminating point, and 



