250 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



have already made repeated mention. This, as may be re- 

 membered, was first explored by Mr. Charles M. Wheatley, of 

 Phcenixville, and part of the material collected placed in the 

 hands of Professor Cope for elaboration. In the present pa- 

 per we have fuller indications of the results than heretofore, 

 and we learn that thirty-four species of mammals, in all, have 

 been obtained, nearly all of them extinct species, and a large 

 proportion of them new to science. Of birds there are two 

 species, a turkey and a snipe ; also two species of tortoises, 

 three or four of serpents, and a few batrachians. Of insects 

 there are thirteen species of coleoptera, and two or three of 

 other orders. In summing up the results obtained from these 

 investigations, Professor Cope calls attention to the inference 

 already drawn by himself and Professor Leidy as to the great 

 difference in character between the post-pliocene fauna of 

 North America and that of previous portions of the tertiary 

 period ; and the fact that, while the miocene mammalia are 

 more or less similar to those of miocene Europe and Asia, and 

 the pliocene vertebrata have a corresponding resemblance to 

 those of the same period of Europe and Asia and the present 

 one of Africa, the post-pliocene resemble, in many particulars, 

 those of South America. 



As, therefore, the difference in these faunas is too great to 

 have been produced in so comparatively short an interval of 

 time bv evolution, if this be admitted as an element, we must 

 look to marked changes in the relative distribution of land 

 and water for the cause. It is therefore supposed that dur- 

 ing the pliocene period, when the geographical affinities of 

 America were westward, especially with Asia, a continent ex- 

 isted in the region now occupied by the Northern Pacific, 

 which formed a connection between the two lands, over which 

 the migratory movements could take place. 



The difference from the South American fauna, at the same 

 time, indicates also a separation by water, and the probable 

 absence of any connection between Costa Rica on the one 

 side and the higher lands of Colombia on the other. The oc- 

 currence then of the glacial epoch brought about the destruc- 

 tion of the pliocene fauna, while, at the same period, the con- 

 nection with Asia was severed by the submergence of this 

 Northern Pacific continent. At the time of the northward 

 retreat of the ice-sheet, mammalian life was probably extinct 



