DELAWAKE COUNTY. 285 



Section at Delaware, Covering the Lower Part of the Huron Shale and the 

 Whole op the Olentangy Shale. 



No. 1. Black slate (Huron shale) 30 ft. 



" 2. Blue shale, without fossils, in thin beds or massive... 8 " 



" 3. Blue limestone 4 in. 



" 4. Shale, like No. 2 1" 4" 



" 5. Blue limestone 3 " 



" C. Shale, like No. 2 5" 



" 7. Alternations of blue shale and black slate 4" 



" 8. Blue shale, like No 2 4" 



" 9. Shale, with concretions of blue limestone that part 

 under the weather conchoidally like massive shale. 

 These hardened calcareous masses are not regularly 

 disposed with respect to each other, but fill most 

 of the interval of six feet. They are six to eight 

 inches thick, and two to three feet wide horizon- 

 tally* 6 " 



" 10. Shale ? (sloping talus), not well exposed 10 " 



" 11. Bituminous, nearly unfossiliferous, limestone, of a 

 black or purplish-black color, hard and crysta line. 

 This black limestone shows a few indistinct bi- 

 valves. One, which is large and coarse, appears to 



be Avicula pecteniformis, Hall; seen 3 " 



" 12. Interval, rock not seen 5 " 



" 13. Section at Little's quarry, in the blue limestone (see 

 page 96). The upper portions of this are quite 

 cherty and pyritiferous. It may be 25" 



Total 101 " 11 " 



Above Delaware the black slate and the Olentangy shale are frequently 

 seen in the left bank of the river. The strike of. the slate runs a little ■ 

 east of the river at the city, jjassing through and forming the bluff on 

 which East Delaware is situated. The concretions of black limestone are 

 from three inches to three and four feet in diameter, and sometimes 

 much larger. Of these Dr. J. S. Newberry says, in the Report of Progress 

 for 1869, p. 19: 



" Much of the doubt which has hung around the age of the Huron shale has been 

 due to the fact that it has been confounded with the Cleveland shale, which lies 

 several hundred feet above it, and that the fossils (without which, as we have said, 

 it is generally impossible to accurately determine the age of any of the sedimentary 

 rocks) had not been found. Yet, with diligent search, we have now discovered not 

 only fossils sufficient to identify this formation with the Portage of New York, but 

 the acute eye of Mr. Hertzer has detected, in certain calcareous concretions which 



* No. 9 here appears the same as No. 6 near the base of the section at Cole's, in 

 Troy township. 



