Section II.: Lines of Communication between the Mississippi Valley and that of the St. Lawrence.

There is no mountain chain between these two valleys; the basin of the great lakes, whose united waters form the St. Lawrence, is separated from the valley of the Mississippi only by a spur of the Alleghany system, not exceeding 450 feet in height, and sinking rapidly down toward the west, so as to be elevated but a few feet above the surface of Lake Michigan. During the rainy season, when the streams are swollen and the marshes of the water-shed are flooded, our Canadian countrymen were wont to pass in boats from Lake Michigan into the Illinois, by the Des Plaines. The breadth of this dividing spur is more considerable than its height. It is not a ridge or crest, but rather a table-land, which imperceptibly merges by gentle slopes into the plains that surround it. Its level summit is filled with marshes, and therefore offers great facilities for feeding the canals which traverse it; further west, where it is scarcely higher than the rest of the country, it is often as dry as the surrounding prairies.