TRIBUTARIES OF THE OHIO IN INDIANA. 185 



State line at Harrison, Ohio, a distance of scarcely 70 miles, the gravel 

 deposits have a descent of 350 feet, or fully 5 feet per mile. The present 

 stream, having cut about 50 feet deeper into the gravel deposits at Harrison 

 than at Cambridge, has a fall of nearly 6 feet per mile. 



CHANGES IN DRAINAGE. 



Possibly the northern part of this drainage basin, like that of the Great 

 Miami, was formerly di-ained westward toward the Wabash, for channels of 

 great depth are occasionally encountered by oil and gas borings in the dis- 

 trict to the west. There is, however, some doubt as to such a drainage 

 course, for the size of the lowfer end of the Whitewater Valley seems to 

 require a drainage area nearly as large as the present, the width of the 

 valley being about a mile and the depth 500 feet. Furthermore, the large 

 valley occupied by the southern part apparently dramed, as now, to the 

 Ohio. The rock floor at Brookville is shown by gas borings to be about 

 490 feet above tide. At a boring 5 miles below Brookville it is only 450 

 feet; while at the mouth of the stream, 1 8 miles farther down, it is less than 

 400 feet. 



TRIBUTARIES OF THE OHIO IN INDIANA. 



Between the mouth of the Great Miami at the east line and the mouth 

 of the Wabash at the west line of Indiana there are no large northern 

 tributaries of the Ohio. This is owing to the fact that the drainage of the 

 greater part of Indiana is toward the Wabash, instead of directly to the 

 Ohio. A tributary of the Muscatatuck heads within 2 miles of the. Ohio 

 near Madison, Ind , and yet leads westward to the East White and thence 

 across the State to the Wabash. Nearly all of the tributaries in southern 

 Indiana head within the limits of the counties that border the river, and 

 consequently have a length of less than 30 miles. Only two. Blue River 

 and Laughery Creek, have greater length. 



In southwestern Indiana, where the altitude is low, the streams have 

 very little fall, and are occupying broad, shallow valleys, which are not 

 infrequently filled to depths of 50 feet or more with marshy alluvium. In the 

 more elevated tracts, whose western border is crossed by the Ohio between 

 Cannelton and Rockport, Ind., the streams present valleys cut to a corre- 

 spondingl)^ greater depth. Their bottoms are narrow and well drained, the 



