344 Proceedings of the British Association. 
gitude, in the 40° to 50° of north latitude. This configuration 
gives great facility for the range of herbivorous quadrupeds from 
north to south, and for the migration of low-flying birds ; whilst the 
Mackenzie furnishes a channel by which the anadromous fish of the 
Arctic Sea can penetrate 10° or 11° of latitude to the southward, 
and the Mississippi enables those of the Gulf of Mexico to ascend 
far to the north. The most remarkable chain east of the Missis- 
sippi, is that of the Alleghanies, which is about one hundred miles 
broad, rises from a base between one thousand and one thousand 
two hundred feet, and attains an elevation from two thousand to 
three thousand feet above the sea. The strip of land between them _ 
and the coast is two hundred miles broad in the Carolinas; be- 
comes still broader in Georgia, and, sweeping round the northern 
extremity of the chain, joins the valley of the Mississippi. This 
strip influences the distribution of animal life, by extending south- 
erly to the 5° of latitude, thus forming also a barrier to the progress 
of anadromous fish from the Atlantic to the bottom of the Gulf of 
Mexico. With reference to physical geography, Newfoundland ap- 
pears as a prolongation of the Atlantic coast line, and its zoological 
and botanical: productions correspond to those of Labrador. When 
the canals already projected shall have opened a communication be- 
tween the several great inland seas which exist in North America, 
an interchange will take place between the fish of widely diverging 
waters. The great proportion of water to land forms a striking fea- 
ture of the north-east continent. This may be zoologically divided 
into two districts, viz. the northern or barren grounds, and the south- 
ern or wooded. The temperature is here materially influenced by 
the inland sea of Hudson’s Straits, and thus its capability of sup- 
porting animal life much affected. On the west of the Rocky 
» the northern corner appears to be similar to the eastern 
side or barren grounds. The general character of the country bor- 
dering the Pacific is mountainous. With respect to the climate of 
North America, the eastern coast has a lower mean temperature 
than the western, at least in the higher latitudes. Probably the 1s0- 
thermal, and even the isothzral lines of the banks of the Columbia 
and New Caledonia, correspond nearly in latitude with those of the 
east coast of Europe. But on the eastern side down to the 56th 
parallel of latitude, the subsoil is perpetually frozen. Even in the 
45th parallel, on the north side of the great Canada lakes, there is 
upwards of six months of continuous frost, and the grallatorial, and 
