STRATIGRAPHY OF EOSSILTFEROUS MEMBERS 137 



Feet Inches 



Clay, Brookville, formerly mined __ 



Clay .._.. 1 



Flint, gray to black, Black Flint 1 8 



Co vere d 52 



Sandst one and covered 40 



Summary 



The Black Flint member forms the uppermost stratum of the 

 Pottsville formation and, in ascending order, the sixth marine limestone 

 of this formation. The deposit is a very local one and occurs only in 

 parts of Jackson and Vinton counties. It consists of iron ore, black 

 flint, and shaly limestone, the latter of which is extremely fossiliferous 

 and is directly associated with the flint. The flinty phase is confined 

 largely to northern Jackson County including Coal and Washington 

 townships, and to southwestern Vinton County including Richland, 

 Clinton, and Elk townships. The flint and limestone vary from 1 

 to 2 feet in thickness, while the ore generally measures from 4 to 8 

 inches. The complete list of fossils obtained from the Black Flint 

 member is given below: 



Lepidodendron sp. 



Fusulina secalica (Say) 



Lophophyllum profundum (Milne-Edwards and Haime) 



Crinoid segments 



Archaeocidaris plates and spines 



Spirorbis sp. 



Fenestella delicatula Ulrich 

 Fenestella remota Foerste 

 Fenestella shumardi Prout ? 

 Fenestella venusta Mather ? 

 Fenestellids undetermined 

 Septopora biserialis (Swallow) 

 Septopora biserialis var. gracilis (Meek) 

 Rhombopora lepidodendroidea Meek 

 Prismopora sereata (Meek) 



Orbiculoidea meekana (Whitfield) 



Rhipidomella pecosi (Marcou) 



Derbya crassa (Meek and Hayden) 



Chonetes mesolobus Norwood and Pratten 



Productus cora d' Orbigny 



Productus semireticulatus (Martin) 



Pustula nebraskensis (Owen) 



Marginifera muricata var. missouriensis Girty 



Marginifera wabashensis (Norwood and Pratten) 



Spiriferina kentuckyensis (Shumard) 



