48 ICHTHYOLOGIA OHIENSIS 



River Ohio 



Head. It is formed by the junction of the rivers 

 Alleghany and Monongahela, in Pennsylvania, at 

 Pittsburgh, near the 40^ degree of north latitude. 

 It is difficult to say which of them is the main branch 

 or stream, the Alleghany being the longest and in 

 the most direct course, while the Monongahela ap- 

 pears to be the largest at the junction, and to have 

 similar waters. 



[I. 301 i.e., 309] [9] Direction. Although the 

 Ohio is exceedingly crooked in its course, its general 

 direction is south west and west south west: it as- 

 sumes every other direction ; but very seldom the 

 opposite one, N. E. 



Mouth. It empties into the Mississippi, near the 

 37th degree of latitude, dividing the state of Ken- 

 tucky from that of Illinois, which lies north. 



Connections. The Ohio is one of the principal 

 branches of the Mississippi, and properly its great 

 eastern branch. The two great western branches, the 

 Arkansas, which is about 1800 English miles long, 

 and the Red River, which measures about 1600 miles, 

 exceed it in length, but not in size, nor in the num- 

 ber of tributary streams ; nor in the extent of their 

 basins. The northern branch or upper Mississippi 

 is much inferior to it in all respects (it is only 775 

 miles long, and receives only seven large rivers,) 

 although it has been mistaken for the main branch. 

 The real main branch is the Missouri, which takes 



