STRATIGRAPHY OF FOSSILIFEROUS MEMBERS 111 



Mahoning County. Excellent exposures of limestone occur at 

 many localities in Mahoning County. In the northern part of Sec- 

 tion 2, Smith Township, one-half mile northwest of North Benton and 

 almost on the county line, the stratum measures 3 feet in thickness 

 and is moderately fossiliferous (Locality 75). The species listed below 

 were obtained: 



Fusulina secalica (Say) 



Lophophyllum profundum (Milne-Edwards and Haime) 



Crinoid segments 



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) 



Spirifer cameratus Morton 



Spirifer opimus Hall 



Squamularia perplexa (McChesney) 



Composita subtilita (Hall) 



The forms below were collected in Little Mill Creek, about two and 

 three-fourths miles northeast of North Benton and just east of the 

 junction of Turkeybroth Creek with Little Mill Creek (Locality 53). 

 The dark fossiliferous limestone measures 3J feet in thickness. 



Crinoid segments 

 Cystodictya carbcnaria (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 



Spirifer boonensis Swallow ? 



Squamularia perplexa (McChesney) 



Composita subtilita (Hall) 



In the eastern part of the county, in Canfield Township, a col- 

 lection of fossils was made from outcrops occurring along Indian Run 

 at a point one and one-fourth miles southeast of Wind School. The 

 limestone measures 3 feet in thickness and is moderately fossiliferous 

 (Locality 76). The species identified are listed below: 



