2l6 CHARLES S. PROSSER 



This formation succeeds the Ohio shale, and as the Cleveland 

 and Erie shales are supposed not to extend to central Ohio it 

 probably rests on the Huron shale in Franklin county. The 

 lower part of the formation in this county is well shown on the 

 eastern bank of Big Walnut Creek east of Central College where 

 the following section occurs : 



Thickness Total thickness 

 feet feet 



No. 7. Till and soil .... - 5 87^ 



6. Fine green argillaceous shale. Bedford shale 7 82^ 



5. Mixed chocolate and greenish shale, mostly 



olive color ._.... 7^ 75/^ 



4. Chocolate shale composed of fine clay - 21% 68 



3. Fine green to olive argillaceous shales. 

 Near base blocky shales containing fossils. 

 Base of Bedford - - - 17% ^A 



2. Fine black shales containing small concre- 

 tions. Huron shale - - - - -24^ 29 



1. Covered to level of Big Walnut Creek \yi &,%. 



The greater part of the formation is shown on Rocky Fork, 

 commencing about one and a half miles east of Gahanna and 

 continuing up the creek for a mile. About one fourth mile up the 

 creek from the ford on the north and south road is an outcrop, on 

 the southern bank, of three feet of black shale which is nearly at 

 the top of the Huron shale. A short distance farther up the 

 creek is a higher bank which gives the following section : 



Thickness Total thickness 

 feet feet 



No. 3. Till - - - - - - - 6% 28^ 



2. Fine chocolate shales of the Bedford - - 7 22 A 

 1. Bedford shales. The upper part is somewhat 



sandy but the grains are very fine, and the 

 lower part is composed of greenish to bluish 

 argillaceous shale. Creek level - - - i$A l SA 



At the second bluff to the west of the private bridge is the 

 following section : 



Thickness Total thickness 

 feet feet 



No. 2. Till ... - -7% 36 



1. Chocolate argillaceous shale which weathers 



to a red clay. Bedford shale. Creek level -28^ 283^ 



