248 On the Fossil Crocodilia of England. 



impressions, and their striking contrast with impressions of 

 rain drops from the same beach, mouth of Carp River, Lake 

 Superior. 



Mr Teschemacher said, that he had seen fossil rain drops, 

 so called, with an elevated ridge crossing them ; an appear- 

 ance easily explained by Mr Desor's hypothesis, but in- 

 compatible with the supposition that they were caused by 

 rain. 



Professor Agassiz said, that on the mud-flats at Cam- 

 bridge, he had noticed impressions made in the way described 

 by Mr Desor at Lake Superior. — American Journal of Science 

 and Arts, vol. x., 2d Series, No. 28, p. 135.* 



On the Fossil Crocodilia of England. 



On reviewing the information which we have derived from 

 the study of the fossil remains of the procoelian Crocodilia, 

 that have been discovered in the Eocene deposits of England, 

 the great degree of climatal and geographical change, which 

 this part of Europe must have undergone since the period 

 when every known generic form of that group of reptiles 

 flourished here, must be forcibly impressed upon the mind. 



At the present day the conditions of earth, air, water, and 

 warmth, which are indispensable to the existence and propa- 

 gation of these most gigantic of living Saurians, concur only 

 in the tropical or warmer temperate latitudes of the globe. 

 Crocodiles, Gavials, and Alligators now^ require, in order to 

 put forth in full vigour the powers of their cold-blooded con- 

 stitution, the stimulus of a large amount of solar heat, with 

 ample verge of watery space for the evolutions which they 

 practice in the capture and disposal of their prey. Marshes 

 with lakes, extensive estuaries, large rivers, such as the 

 Gambia and Niger that traverse the pestilential tracts of 

 Africa, of those that inundate the country through which 



* Many of the so-called fossil foot-marks will, we believe, turn out to be 

 imaginary. — Edit. Ed. Ph. Journal. 



