THE region occupied by the river system of the Ohio contains an assemblage of States which vary greatly in most of their characteristics, yet they present certain common features which make it desirable to consider them in one description. The surface of nearly all this area lies at a considerable height above the sea. Excepting a small part of the field near where the Ohio joins with the Mississippi, the elevation of the country exceeds one thousand feet above the ocean level, and a large part of its surface attains an elevation of more than two thousand feet. On the northern border the basin of the Ohio is but slightly separated by the valley in which lie the Great Lakes of North America. On the cast the head-waters of the stream descend from the loftiest portion of eastern North America. On the south the basin is parted from the Gulf district by the low spurs of the southern Appalachian system. On the west and southwest it lies wide open to the central part of the Mississippi Valley. The whole area of Kentucky and of Tennessee, except a narrow fringe of land in the western part of these States, drains directly into the Ohio River. The greater part of Illinois, Indiana, Ohio, and West Virginia, a portion of western New York, Virginia, North Carolina, Georgia, and Mississippi, contribute waters to its stream. No other river basin of equal area on this continent has the land it contains so well placed for the uses of our race, the soil so fertile, or the underlying earth so rich in mineral resources as this district of the Ohio.
The climate of this region is characterized by the existence of a tolerably long-continued summer or growing season, the duration of which in the northern and southern field varies considerably. In northern Ohio there is ordinarily some sign of springtime visible by the middle of March, but frosts continue until the first days in May. In northern Alabama the vernal season sets in