FRANKLIN COUNTY. 643 



these beds has been made, but they are as rich in this material, to all 

 appearance, as any of the exposures in the State, and not less than 

 twenty per cent, of bituminous substance has been found in the south- 

 ern outcrops. 



The formation is of special interest in establishing the unity of the 

 series of rocks that make up the floor of the State. It is a wonderfully 

 persistent bed, as is shown by the records of deep boringsmadefar to the 

 eastward. Southward, it has been traced trom Ross county to the Ohio 

 River. It undoubtedly exists in Pickaway and Fairfield counties, 

 though its presence has not been determined in either, except at a point 

 just beyond the Franklin county line, to the S9uth of Canal Winchester. 



It marks a period of deeper submergence of the regions where it is 

 found than that which characterized the Waverly. The latter forma- 

 tion has abundant signs of shallow water in its beds, as sun-cracks, rip- 

 ple marks and oblique" stratification, but nothing of this is seen in the 

 black shale. 



We learn, then, that the deeper submergence of the Huron shale in 

 which three hundred feet of fine and even sediments were gathered on 

 the ocean floor, was followed by a period of elevation, in which at least 

 one hundred feet of shales and sandstone were accumulated at very little 

 depth below the surface. The shore line itself is often seen in the ripple- 

 marked layers of the Waverly. But this period of elevation was brought 

 abruptly to an end, and the conditions of the earlier Huron were, for a 

 time, restored. A deeper sea and abundant marine life — especially of 

 sea-weeds and fishes — are attested by the fifteen to sixty feet of the Clev- 

 eland shale, followed in turn by re-elevation of the ocean floor for the 

 growth of the later Waverly beds. 



An outcrop of black shale, on the farm of Lorenzo Taylor, Esq., of 

 Plain township, may prove to belong to the Cleveland shale; and other 

 exposures will possibly be found in other portions of Plain and Jefferson 

 townships. 



III. DRIFT. 



The Drift deposits of the county are far more important than the bed- 

 ded rocks on which they rest, so far as useful applications are concerned, 

 for they furnish its soils and water supply, and all of the minor modifi- 

 cations of the surface upon which drainage and tillage depend, are 

 much more closely connected with them than with the rocky substratum. 

 The drift of Franklin county falls into the two great divisions that ap- 

 pear in so many other parts of Ohio, viz., the unstratified and the strati- 

 fied deposits. Both of these are shown with perfect distinctness, but by 



