PINE-BARREN FLORA 
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 !a 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 liortensis, 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 southern 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 forms confined to the eastern States. The 
* Hollick, A., “ Plant Distribution,” pp. 191—201. 
