PINE-BAEEEN FLOEA 141 



Now this flora has a curiously discontinuous range further 

 north-eastward. It disappears from the mainland almost 

 entirely, but reappears on Staten Island and Long Island. 

 Still further east comes a stretch, of eighty miles of sea, 

 beyond which the pine-barren flora once more is in evidence 

 on Martha's Vineyard and Nantucket Islands. On a limited 

 stretch of the opposite mainland, near New Bedford, the same 

 flora again makes its appearance. Further north, isolated 

 members of the flora such as Magnolia glauca, from near 

 Cape Ann, are known from certain coastal tracts. 



It might be argued that this discontinuous distribution is 

 due to marine currents or winds, but both the prevailing 

 winds and the currents set in from the opposite direction. 

 It would not explain the fact, moreover, that the pine-barren 

 flora is almost limited to the islands. Hence it seems more 

 likely that Long Island was connected by land with Cape 

 Cod, forming la continuous strip of- land, which was separated 

 from the mainland by a broad river or a lake, as Mr. Hollick* 

 suggests. Mr. Hollick's theory not only explains the method 

 of dispersal of the southern pine-barren flora, it gives us a 

 clue to the problem why the northern Helix hortensis, which 

 has evidently survived as a relict form, should be almost 

 confined to the islands off the coasts of Maine and Massa- 

 chusetts. However, while I believe that much of that land 

 which lay off the Atlantic coast remained unaffected by the 

 Glacial deposits, and that the sou,thern flora survived the 

 Glacial Epoch on these islands, Mr. Hollick considers the 

 eastward extension of Long Island, and with it the pine- 

 barren flora, of post-Glacial age. 



I have mainly dealt with reptiles and amphibians in this 

 chapter, because they form a very characteristic feature of 

 the north-eastern States. Besides no opportunity occurred 

 of mentioning them in the earlier part of this volume. 

 The mammals, on the other hand, scarcely need further 

 comment here. Only comparatively few species are peculiar 

 to this province. Nevertheless, there is an order which 

 has not hitherto been alluded to, and which contains 

 some remarkable form's confined to the eastern States. The 



* Hollick, A., " Plant Distribution," pp. 191—201. 



