The most considerable rivers intersecting this section of country are the Muskingum, Sciota, Big Miami, and Wabash, all of which, in the spring season, are navigable two or three hundred miles from their mouths. The valleys of these rivers give place to many extensive and fertile bottoms well adapted to cultivation, and producing the necessaries of life in great abundance and variety. The plain, or rolling country, is separated from that last under consideration by the imaginary line above mentioned. It is not to be inferred, however, that the junction of these two regions is distinctly marked by any characters whatever by which the line can be traced with precision, but that a gradual change of aspect is observable in travelling from one variety of country to the other, and that the general direction of the line indicated by this change is that specified above. The other boundaries of this variety are the Mississippi on the west, and the Lakes Erie and Michigan, and the Fox and Wisconsan rivers on the north and east. This variety of country, although not entirely destitute of hills, is almost throughout its whole extent possessed of an undulating or rolling surface, rising into broad and gentle swells in some parts, and subsiding into extensive flats or plains in others. The valleys of numberless watercourses, bounded by abrupt bluffs or banks, afford some diversity to its aspect; and the bluffs in {203} particular of the principal streams, being cut by numerous ravines, contribute in many places to give the surface a hilly and broken appearance. Although no part of this region can with propriety be denominated hilly, especially when compared with the portions of country above considered, yet upon the Wisconsan, Fox, the head-waters of Rock and Melwakee rivers, the country is considerably diversified with hills, or rather swells, and valleys. The only hills worthy of particular notice, not only in this variety, but in the whole section under consideration, are the Ocooch and Smokey mountains, which are broad and elevated ridges rather than mountains. The former is situated about twelve miles north of the Wisconsan, one hundred miles above its mouth, and the latter about forty miles south of the portage between the river just mentioned and Fox river of Green Bay. The rivers of most note within this region are, the Wabash, above the hilly country before described, the Kaskaskias, Illinois, Rock and Wisconsan, tributary to the Mississippi; the Fox of Green Bay, the St. Joseph of Lake Michigan, and the Maumee and Sandusky, tributary to Lake Erie. These rivers are all navigable for boats of ten or fifteen tons burden when swollen by spring freshets; but, during the greater part of the summer and fall, they have not a sufficient depth of water for boats of burden, and in winter their navigation is entirely obstructed by ice. The spring freshets, consequent to the melting of the snow and ice,