Another physical similarity between the two continents might be found in the relations of the Gulf of Mexico to the northern continent and the great Argentine plain to the southern; both lie in the same position with regard to the eastern and western mountain chains, though the one is submerged.
But the differences are also great. The main drainage system of the central plain in North America is to the south, by the Missis sippi; that in South America is to the east, by the Amazon; while the Great Lakes are a great drainage system for the surrounding regions, the melting snows of which supply them through deep rock fissures. They are hollows in the oldest rock elevation of the continent, with the ground sloping away from them in every direction not far from their shores; not a single considerable stream flows into them, nor even into the Saint Lawrence west of Montreal. The most vital difference structurally is due to the position of the west ern chain. In North America the chief height is on the eastern flank a thousand miles' from the Pacific, the gradually lessening slopes leav ing space for an empire along that ocean, and their drainage forming great rivers. In the southern continent it hugs the ocean so closely that not a stream of any size flows into the sea, and the cultivable area is but a petty strip on the coast. More than half the whole western side of South America is occupied by one state, some 1,500 miles long by 50 or 60 wide, which even so finds none too much terri tory with its slender width and partly barren soil. The northern continent has also an im mense advantage in the character of its coast line: what with its archipelagoes, sounds and river-mouths in the north, and the sheltered in dentations farther south, it is well fitted for commerce, while the whole South American coast has very few good harbors above Pata gonia. The greatest differences in the civil ized destiny the two continents, however, are due to the northward massing of the land heretofore mentioned. All the United States and southern Canada lie in the temperate re gions; the largest and most fertile part of South America lies in the tropics. The narrow
southern part of North America lies in the warm semi-tropic ocean ; that of South America in the south-polar sea. A quarter of all North America is a worthless polar waste, but per haps as large a space of South America is an uninhabited and pestilential tropic jungle; and the improvements in food production and means of warmth which push back the reign of the one are perhaps balanced by the hygienic in ventions and commercial uses tending to re claim the other. Certainly the northern part has much more arable land and much less miasmatic or enervating climate than the other, nothing whatever that compares with the pestilential coasts and inland swamps of the southern. The Mississippi Valley, the largest continuous body of agricultural land on the earth, is not only of immensely greater value than the grassy steppes of the temperate south ern plain of South America, but the prairies of the north, which correspond in position to the Amazonian forests in the south, are a still more striking contrast. Commercially the north is equally favored in comparison. From the nearness of the continent to Europe rela tively to Asia, and from the structure of the continent throwing the mass of population and production east of the great mountain chain, the chief commercial relations of America must always be with the western side of the other continent. But North America is di rectly opposite Europe, the commercial head of the world; while South America's eastern neighbor is barbaric Africa, and most of its harbors are either along the miasmatic north ern and northeastern coast, unfit for great cities, or the semi-polar shores of Patagonia.
For general works on American• geography and topography consult the New Universal Geography,' translated by Keane and Raven stein from Elisie Reclus' French work (1890 94) ; Dawson's 'North America, Canada and Newfoundland) (18971; Keane's 'Central and South America) (1901) ; Shaler's (Nature and Man in (1891) ; Wright's (Ice Age in North America) (1889) ; Powell's (Physio graphic Regions of the United States) in tional Geographic Monographs) (Vol. I, 1895).