FEANKLIN COUNTY. 607 



limestone completes the series so far as it is shown in Franklin county, 

 holding everything between the bone bed and the blue shales which con- 

 stitute the base of the Huron shale. 



The Hamilton group, a very important member of the Devonian system, 

 is due in this interval, and there is no reason whatever to doubt that 

 some of these upper beds, perhaps a considerable portion, were formed in 

 that period — but no one has yet been able to point out the line of divi- 

 sion, stratigraphical or paleontological, in this series, that separates the 

 Hamilton from the Corniferous. In northern Ohio, Dr. Newberry finds 

 a series of shales interposed between the Sandusky (Delaware) limestone 

 and the Huron shale, which contains so strong a preponderance of true 

 Hamilton fossils as to deserve to be called by this name. The apparent 

 stratigraphical equivalent of these Hamilton shales, is the bed of blue 

 shales designated by Prof. Winchell the Olentangy Shales, to which refer- 

 ence has already been made in preceding pages, as lying at the base of 

 the Huron shale. In this county, however, it has proved non-fossiliferous 

 wherever examined. There are, indeed, but very limited exposures of it. 



Two additional sections of the Columbus limestone will now be de- 

 scribed, somewhat in detail. They are found in the two belts of quarries 

 that have been most extensively worked, both for building stone and 

 lime, viz. : the quarries on the east bank of the Scioto, three miles above 

 Columbus, near the railroad, bridge of the Piqua (P. C. & St. L.) Road, 

 and known originally as the Medary quarries, but latterly as the Smith 

 and Price quarries, and the " State quarries," located due west of the city, 

 on the further bank of the Scioto River. From these quarries, the stone 

 of which the Capitol is constructed, was derived, the State having pur- 

 chased the lands which they occupy, and still retaining the ownership. 



The Smith and Price section will be first considered. The annexed 

 wood cut represe'nts it. The total thickness of the beds shown in the 

 quarries is thirty-three feet. It does not reach as low an horizon as the 

 section already described, and it includes only the bottom layers of the 

 Delaware beds. 



The lowest bed reached here is a three-feet course — quite flinty in com- 

 position.' It is not raised in large blocks, and the flint prevents it from 

 being easily worked. There is, therefore, no sufficient reason for work- 

 ing it, and it is generally undisturbed, except when drainage or track- 

 laying reaches it. The same can be said of the " two-foot course" that 

 overlies it. This course has a double layer of flint nodules, and probably 

 belongs to the same horizon with the flint nodules of the first section. 

 The layers that immediately succeed this, constitute the most valuable 

 stone of the quarry. 



