16 GEOLOGY OP OHIO. 



another well, bored twenty miles above the mouth of the river, pipe was 

 driven through clay and sand to the depth of 220 feet; the well begin- 

 ning less than ten feet above the surface of the stream. In the valley of 

 Grand river, at Painesville, Gen. J. S. Casement drove a pipe 70 feet 

 below the level of the stream without reaching the rock. Rocky river, 

 seven miles west of Cleveland, runs in a trough which has rock bottom 

 and sides ; it therefore shows an exception to the general rule which has 



_ Profile Section across the Cuyahoga Valley. 



^^z^j^^^^^^^^-m^. 



,. Conglomerate. 4- Bedford shale. 7- Old Flood plain. 



z. Cuyahoga shale. 5. Cleveland shale. 8. Erie clay in old valley. 



3. Berea grit. 6. Erie shale. 



been indicated; but a little west of the present mouth of Rocky river we 

 find its ancient channel, now filled with clay, which extends to an un- 

 known depth below the lake-level. Two miles above its mouth, Rocky 

 river breaks into this old channel, and one of its banks is composed of 

 clay, the other of rock. From this and similar instances we learn that 

 the old channels of rivers were sometimes filled to the brim by subse- 

 quent submergence, and wh^n, ages after, these lines of drainage were 

 re-established, new channels were formed, which have since been cut, in 

 some cases, to the depth of 100 feet in solid rock. 



In parts of our country outside of Ohio, and in Europe, buried river 

 channels, similar to those I have described, have frequently been met 

 with. The filled-up channel of the Genessee at Portage, described by 

 Prof. Hall in the Geology of the Fourth District of New York, pre- 

 sents a case resembling that of Rocky river, just cited. Onondaga lake 

 lies in an old excavated channel mainly filled with gravel, sand, etc. 

 This channel is cut through the Onondaga salt-group, and the Salina 

 salt wells are bored in it. The deepest of these extends 414 feet below 

 the surface level of the lake, i. e. 50 feet below the sea level, and it is not 

 certain that rock was reached in this. — (Geddes Trans. N. Y. State Agri- 

 cultural Society, 1859.) The long level of the Erie canal between Utica 

 and Rome lies in the old, partially filled valley of the Mohawk, in which 

 the rocky bottom is far below the surface — how far is not known, as it 



