The northern shores of Lake Ontario and Erie, the western shore of Lake Huron, and the general surface of the valleys of the Ohio, the Illinois, and the Mississippi, afford a highly productive soil. More to the southward, the extended valley of the Tennessee is one of the most fertile portions of the republic; and the same fertility extends itself beyond the Mississippi below the Missouri, until it is checked by the Ozark Mountains, whose productive portion is confined to the valleys. To the west of these mountains, and of the Missouri, the soil becomes less and less fertile, till we reach the Great American Desert, which has already been described. The eastern shores of Lake Michigan, and the southern coast of Lake Superior, are either sandy or rocky, and generally barren. Among the Rocky Mountains are sheltered and fertile valleys, though their summits are of course rocky, sterile, and covered with snow the greater part of the year. The timber in the mountains is pine, spruce, fir, and other terebinthines. Though deficient in timber, the terrace plains below have generally a fine soil. The prairies, like those in the Mississippi valley, are covered with coarse grass and a variety of beautiful flowers. Among the prairie plants are two or three kinds of roots, which furnish food to the savages. Wild sage is found in abundance; it grows of the size and height of a small tree, and on these extensive plains is one of the principal articles of fuel. For a considerable distance into the interior, the seashore is skirted with deep and thick forests of evergreen. On the whole, it is believed that few countries on the earth have a more fertile soil, than the valleys west of the Rocky Mountains.