288 GEOLOGY OF OHIO. 



This shaly limestone near the base of the Olentangy shale is immedi- 

 ately underlain by a very hard crystalline limestone, which is sometimes 

 black, but frequently purplish, containing pyrites in abundance and 

 very few evident fossils. It is exposed and quarried just below Waldo, 

 in Marion county, but is nowhere wrought in Defiance county. It is a 

 persistent layer, and occurs in Defiance county. In the report on the 

 geology of Marion county it has been referred to the Hamilton, where it 

 probably belongs, and seems to represent the Tully limestone of New 

 York. 



The following section in the Olentangy shale will further illustrate 

 the bedding and nature of this member of the Devonian. It occurs 

 along the banks of a little creek that enters the Olentangy River from 

 the west, on land of F. Bartholomew, south-east of Powell : 



Section in the Olbntangy Shale, in Liberty Township. 



No. 1. Black slate, with black limestone concretions 20 ft. 



" 2. Blue shale, bedded like the slate, but softer 3" 



" 3. Black limestone, in a broken, lenticular, or concretionary 



course 8 in. 



" 4. Same as No. 2 5" 4" 



" 5. Black slate 2" 



" 6. Shale, same as No. 2 2" 



" 7. Blue, irregular, shaly limestone, appearing concretionary ; 

 the same as that washed out of " blue clay" near "Waldo ; 



comes out in blocks ; in one course 4 " 



" 8. Same as No. 2 10" 



" 9. Same as No. 5 3" 



•' 10. Same as No. 2 2 " 



"11. Same as No. 5 1 " 



"12. Same as No. 2 6 " 



"13. Same as No. 5 „._ i " 



" 14. Same as No. 2 1 " 2 " 



"15. Same as No. 5 4 « 



" 16. Same as No. 2 1 «< 



"17. Same as No. 5 1 " 



"18. Same as No. 7 8 " 



" 19. Shaly (not well seen) 15 " •> 



" 20. Hard, dark blue, bituminous limestone, with much chert 

 and pyrites ; the chert is black, and hard as flint ; beds 



three to twelve inches (well exposed) 9 " 6 " 



21. Thinner blue beds, with vermicular or fucoidal marks, and 

 little chert; fossiliferous ; sometimes coarsely granular and 

 crinoidal, but mainly earthy or argillaceous, and tough 

 under the hammer ; within, this is in beds of six to twelve 

 inches 6 " 



