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90 POTTSVILLE FAUNA OF OHIO 



Description of Geologic Sections and Collecting Localities 



Jackson County. Fossils were collected from the Lower Mercer 

 ore at only one locality, from outcrops along the road in the eastern 

 part of Section 10, Coal Township, just east of Grace mine. The 

 stratum is dark red in color, coarse and siliceous in character, and spar- 

 ingly fossiliferous. The section measured here follows (Locality 56): 



Feet Inches 



Coal 6 



Clay 2 



Shale 4 7 



Ore, Lower Mercer __ 5 



Shale . 3 



Covered 5 3 



Shale, blue 5 



Limestone, gray, fossiliferous 1 



Shale, dark, fossiliferous > Lower Mercer. 



Limestone, blue, fossiliferous J 



The fossils collected here are as follows: 



Derbya crassa (Meek and Hayden) 

 Productus cora d'Orbigny 

 Spiriferina kentuckyensis (Shumard) 

 Spirifer opimus Hall 

 Composita subtilita (Hall) 



Parallelodon sangamonensis (Worthen) 

 Allerisma terminale Hall 



Euphemus carbonarius (Cox) 

 Pleurotomaria sp. (fragment) 



SAND BLOCK ORE 



Stratigraphy and Extent 



In ascending order the Sand Block ore is the next faunal horizon 

 above the Lower Mercer ore. It is of limited stratigraphic extent and 

 has been found only in Lawrence, Scioto, and Jackson counties. Its 

 position with reference to the Upper Mercer or No. 3a coal varies much 

 from place to place; sometimes it is found directly above the coal, 

 while sometimes the two horizons are separated by an interval of 30 

 feet, as in parts of Scioto County. In Lawrence County the distance 

 varies from 1 to 15 feet, and in southern Jackson County 10 to 20 

 feet is generally found. In the northern part of the latter county 

 the ore lies just above the Upper Mercer coal. In Scioto County it is 

 also found 10 to 20 feet below the Upper Mercer ore. 1 



'Stout, W., Geol. Surv. Ohio, Fourth Ser., Bull. 20, pp. 160, 297, 580, 1916. 



