82 POTTSVILLE FAUNA OP OHIO 



tremely fossiliferous shale often occurs below the limestone. The 

 average thickness is about 3 feet, the lower bench being thinner and 

 more fossiliferous than the upper. One of the best outcrops occurs in 

 the western part of the county along Little Mill Creek, about two and 

 one-half miles northeast of North Benton and one-fourth mile west of 

 the junction of Turkey broth Creek with Little Mill Creek. Here the 

 stream has formed a waterfall over a projecting ledge of hard Lower 

 Mercer limestone. The deposit consists of two benches of tough, al- 

 most black limestone, without partings, the upper one of which is flinty 

 at the top. The lower bench is very fossiliferous and affords excellent 

 collecting. The section measured here follows (Locality 53): 



Section along Little Mill Creek, Berlin Township, Mahoning County 



Feet Inches 



Limestone, Upper Mercer 3 4 



Covered 5 3 



Shale, black 2 



Coal, Upper Mercer or No. 3b __ 10 



Shale, black __ 7 



Clay 5 



Shale, gray 1 



Sandstone, shaly 5 4 



Shale, sandy, gray 7 6 



Limestone, hard, flinty near top, fossil-1 



iferous V Lower Mercer. ~_- < s 2 



Limestone, very fossiliferous J l^__ 6 



Shale, clay-__. _. 1 



Coal, Middle Mercer "_ _. 2 



Shale, clay, gray 1 



Covered 2 



Shale, clay, bluish-gray__ 1 



Sandstone, .shaly, micaceous 2 



The fossils collected at this locality include the following forms: 

 Crinoid segments 



Septopora biserialis var. gracilis (Meek) 



Cystodictya carbonaria (Meek) 



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) 



Spirifer cameratus Morton 



Spirifer opimus Hall 



Squamularia perplexa (McChesney) 



Composita subtilita (Hall) 



Orthoceras n. sp. 



