STRATIGRAPHY OF FOSSILIFEROUS MEMBERS 91 



The Sand Block ore appears locally in patches, and in Lawrence 

 County is found only in a few localities. It is nodular, highly siliceous in 

 composition, and generally very thin, varying in thickness from 1 

 inch to slightly more than 1 foot, with an average of 5 inches. It is 

 poor in fossils, and the forms which are present are microscopic in size. 

 As the iron content in the ore is low, it is not used commercially at the 

 present time, although formerly it was utilized to some extent for 

 smelting in the old charcoal furnaces of Jackson County. 



Description of Geologic Sections and Collecting Localities 



Scioto County. In the following section, measured on the land of 

 Smith Hayward, Section 35, Bloom Township, the general relations of 

 the Sand Block ore to the Upper Mercer or No. 3a coal below, and to 

 the Upper Mercer ore above, are well shown. 1 No collections of fossils 

 were made. 



Feet Inches 



Coal, Tionesta or No. 3b .2 



Covered . 18 



Ore, Upper Mercer 1 6 



Covered 16 



Ore, sparingly f ossilif erous, Sand Block 1 



Shale 10 



Coal, Upper Mercer or No. 3a 1 6 



Jackson County. The ore outcrops in the Dever Valley on the 

 land of Joseph Woods, Section 24, Hamilton Township. It is moder- 

 ately fossiliferous, the remains consisting mostly of small fragments of 

 very diminutive shells which have for the most part been decomposed 

 to a white, chalky substance. The white color of the shells presents a 

 striking contrast to the coarse-grained, dark red matrix. The geologic 

 section here follows (Locality 57) : 2 



Feet Inches 



Ore, Upper Mercer _. 4 



Covered 13 



Ore, very f ossilif erous, Sand Block __ 4 



Shale and covered 27 



Ore, Lower Mercer __ 1 



Clay, light 1 



The fossils found in the Sand Block ore from this locality are listed 

 below: 



Orbiculoidea sp. 



Minute Pelecypoda (three or more species) 



Minute Gastropoda (three or more species) 



^tout, W., Geol. Surv. Ohio, Fourth Ser., Bull. 20, p. 579, 1916. 

 2 Idem., p. 162. 



