XX INTRODUCTION. 



therium, Dichobune, Palneotherium, and Lophiodon, show- 

 ing, with the fossils from the London clay, that the same 

 peculiar generic forms of the class Mammalia prevailed 

 during the eocene epoch in England as in France. 



Almost the sole exception to the generic distinction of 

 the Eocene Mammalia which occurred in the researches 

 of Cuvier, was the famous Didelphys of Montmartre : and 

 what made this discovery the more remarkable was the 

 fact that all the known existing species of that marsupial 

 genus are now confined to America, and the greater part 

 to the southern division of that continent. An Opossum 

 appears to have been associated with the peccari-like 

 Hyracotherium in the eocene sand of Suffolk ; where, like^ 

 wise, some teeth of a Monkey, apparently a Macacus, have 

 been found. It is not uninteresting to remark that the 

 Peccari, the nearest existing ally to the old Hyracothere, 

 is, like the Opossum, now peculiar to America ; and that 

 two species of Tapir, the nearest living allies to the Lo- 

 phiodon, exist in South America. We gain little, how- 

 ever, from the comparison of the eocene with the exist- 

 ing Mammalia, in reference to their geographical distri- 

 bution, except a strong indication that the relative dis- 

 tribution of land and sea, as well as the climate of En- 

 glish latitudes, were then widely different from what they 

 .are at the present day. 



The marine deposits of the eocene epoch, in contrast 

 with those of the preceding secondary periods, also be- 

 speak the great advance of animal life, and show the re- 

 mains of great Whales. Petrified cetaceous bones have 

 been found in situ in the London clay at Harwich ; and 

 similarly petrified teeth and ear- bones, " cetotolites," have 

 been washed out of the eocene clay into the Red-crag at 

 Felixstow. These fossils, however, belong to species dis- 



