CHAPTER LXXXIV. 
REPORT ON THE GEOLOGY OF FRANKLIN COUNTY. 
BY EDWARD ORTON. 
I. SITUATION AND TOPOGRAPHY. 
Franklin county is bounded on the north by Delaware county, on the 
east by Licking and Fairfield, on the south by Pickaway, and on the 
west by Madison. Union county touches it also on one corner, furnish- 
ing a very small portion of the northern and western boundary. Its 
position in the State is very nearly central. A nearer approximation to 
an exactly central location, could have been secured by combining por- 
tions of Delaware and Franklin counties in one county. 
Its topography is very much more varied than that of any of the coun- 
ties that lie along the same parallel to the west of it, the valleys of the 
Scioto and its tributaries constituting the chief features. This first 
named valley divides the county into two main divisions, the eastern 
division having the larger area. Its course, from the northern border to 
the center of the county, is-south-easterly ; from this last named point 
to the line of Pickaway county, its direction is very nearly south. Sey- 
eral of the principal tributaries of the Scioto do not enter it within the 
limits of the county,.but they run in north and south valleys approx- 
imately parallel to the main valley, until they pass the southern 
boundary. ; 
The north and south direction of the tributary valleys, as well as of — 
the main valley, is a characteristic of the county, especially of the 
northern half. It is well shown by a section taken from west to east 
along the southern line of Sharon township. Beginning on the west 
side of the county, with the well-marked valley of Big Darby Creek, we 
find a dividing ridge, about eight miles in breadth, from which we de- 
scend into the Scioto Valley. A second stretch of table land, about five 
miles wide, carries us to the Olentangy Valley. The intervening high 
ground between this and Alum Creek Valley, is not far from seven miles 
in width, while not more than three miles separate the Alum Creek 
Valley from the Big Walnut Valley. About four miles intervene 
f 
