INTRODUCTION OF FOREIGN SPECIES. 155 
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rior, and in Nova Scotia is said to be the most common 
of the larger species. That it should occur on the 
extreme point of a cape extending far into the sea, and 
on desolate islets along the coast, is consistent with the 
supposition of its having been borne there by currents ; 
while the common mode of distribution, by numerical 
increase and extension, or by direct introduction through 
commercial agency, from Europe, does not exjjlain why 
it is found in such unfrequented spots only, on the bor- 
ders of the sea alone, never upon the main land, and on 
some islets, but not on others. Our own hypothesis is, 
that having been very early introduced into the French 
province of Acadia, (and also into Canada) by the 
European colonists, and become numerous there, it has 
been borne along the coast by counter currents and 
eddies, to the places which it now occupies, where, being 
protected from other animals, and from the operations of 
agriculture, to which it would have been exposed on the 
main land, and under the influence of a climate rendered 
mild by the proximity of the sea, it has multiplied to a 
great extent." 
1 Since the above observations were penned, the author has again 
visited, after an interval of nine years, the locality upon Salt Island, 
Cape Ann. This island, which at extreme low water is connected with the 
main by a narrow sand-bar, is a mass of granite elevated not more than 
sixty or seventy feet above the sea ; its seaward side is bold and precipitous, 
and being open to the assaults of the waves, is denuded of soil to the very 
summit. Its landward side, protected by the crest of the island from 
storms corning from the ocean, has a thin superstratum of soil, which sup- 
ports a rank growth of coarse grass and low shrubs, the latter affording a 
