340 THE GEOLOGY OF THE LABRADOR COAST. 



fauna. Certain common Syrtensian and purely arctic 

 forms there dwindle in size and diminish very sensibly in 

 numbers, and a few arctic species are replaced by Aca- 

 dian forms. 



At Point Shirley we have good evidence of the begin- 

 ning of the Virginian fauna, where Venus mercenaria 

 and Buccinum plicosum abound. This must have been 

 the northern limits of the fauna so well developed, as 

 noticed by Desor, in the beds of Nantucket, where the 

 temperature of the sea could have scarcely differed from 

 . that of the present period. The same may be said of 

 the post-tertiary fauna of South Carolina, and, from 

 what little we know, of that of Florida, where the heated 

 Gulf Stream evidently preserved the same conditions as 

 now, only more checked in its northern limits than at 

 present by impinging more directly on a coast lined with 

 floating ice, as that of Maine must have been in post- 

 tertiary times. 



At such a time the increased degree of moisture must 

 have produced a much greater rainfall, the fogs must have 

 been of greater extent, and the snow line must have ap- 

 proached much nearer the sea, than at present, on the 

 eastern coast of America, south of lat. 60°, and glaciers 

 of great extent must have surrounded the mountains of 

 New England. The land fauna and flora of New Eng- 

 land must have been that of Labrador. The Greenland 

 seal {Phoca [Pagophihis\ groenlandica), the Beluga ver- 

 montana, and among plants the Potentilla tridentata 

 and Arenaria groenlandica (both of which are now 

 found in the colder parts of the coast of Maine) must 

 have been the characteristic species. Remnants of such 

 a flora and fauna we now behold on our alpine summits. 



