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 

 Mountains, 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 iso- 

 thermal, and even the isothseral 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 



