Drainage Changes near Granville^ Ohio 165 
altitude, the altitude above sea-level of the rock-bottom is here 
I approximately 646 feet. The A. R. Wright w^ell, located about 
' five miles west, also in the valley bottom, has an altitude of 
i 930 less 170, or 760 feet above sea level. The Colville well, 
I three-fourths of a mile east of Alexandria and very close to the 
i debris divide between the valleys of the Raccoon and Brushy 
D Fork, has an altitude of 931 less 238 or 693 feet. While for the 
purpose of logical treatment it is desirable that all data should be 
Fig. 2. Topography of the region about Granville, based on “advance copies” 
of the Newark and Granville sheets supplied by Mr. J. H. Jennings, Geographer, 
U. S. Geological Survey. 
secured from corresponding points relative to the valley center, 
f it is impossible to determine absolutely whether the data given 
j conforms to this. Nevertheless it seems safe to conclude from all 
I the drillings, including several in addition to those given above, 
j that the altitude of the rock-bottom west of the Sinnett well gradu- 
ally rises as it approaches Alexandria. The Colville drilling, though 
west of the Wright well, has a much lower rock bottom and prob- 
ably lies near the center of the old Alexandria river. 
