STRATIGRAPHY OP FOSSILIFEROUS MEMBERS 99 



Deltopecten scalaris (Herrick) 

 Acanthopecten carboniferous (Stevens) 

 Astartella concentrica (Conrad) 

 Astartella varica McChesney 



Muskingum County. In Section 32, Newton Township, along the 

 diagonal road one and one-half miles northwest of Roseville, the Upper 

 Mercer member is exposed (Locality 64). It measures ten inches in 

 thickness, and consists of a lower layer of dark gray limestone con- 

 taining flint nodules and an upper layer of black flint in which large, 

 branching tubes, either hollow or filled with a soft limonitic decomposi- 

 tion product, are abundant. The filling of the tubes seems to have 

 originated as concretionary structures of iron ore, although the re- 

 semblance to plant stems is very marked. The flint is extremely poor 

 in fossils both in number ^of species and individuals, and the following 

 represent the only species which were discovered: 



Fusulina secalica (Say) 



Cystodictya carbonaria (Meek) 



Marginifera wabashensis (Norwood and Pratten) 



In Hopewell Township the member is rarely present as a limestone 

 but is represented by black flint. The following geologic section was 

 measured along the Flint Ridge Road in Section 8, about one mile 

 northwest of Poverty Run School. Although fossils are scarce, good 

 collecting is afforded as the locality is easy of access (Locality 65) : 



Feet Inches 



Shale and covered 15 



Flint, black, Upper Mercer 2 



Clay and covered 5 



The fossils below were collected: 



Fusulina secalica (Say) 



Girtyina ventricosa (Meek and Hayden) 



Crinoid segments 



Productus semireticulatus (Martin) 

 Squamularia perplexa (McChesney) 



Pleurotomaria sp. ? 



Along Flint Ridge, both in Hopewell Township, Licking County, 

 and in Hopewell Township, Muskingum County, the black flint is well 

 developed, and was used to some extent by primitive man in Ohio for 

 the manufacture of weapons, arrowheads, and implements of various 

 sorts, for which purpose the flint seems especially well adapted. . Some 



