STRATIGRAPHY OF FOSSIL1FEROUS MEMBERS 83 



Near the central part of the county a collection was made from 

 exposures of Lower Mercer limestone in the bed of West Branch of 

 Meander Creek, one-fourth mile east of Club Lake and one-half mile 

 south of Ellsworth. The stratum is very hard and flinty toward the 

 top where the fauna is small and stunted. A thin, extremely fossilifer- 

 ous zone occurs about 3 inches above the base of the horizon. The 

 geologic section here follows (Locality 54): 



Feet Inches 



Sandstone, massive, base very irregular, coarse-grained, 



ferruginous, rich in plant fossils 26 



Coal, Upper Mercer or No. 3b 1 4 



Sandstone, irregular base __ 2 



Clay, plastic _ 4 4 



Shale, gray, siliceous, micaceous, rich in plant fossils 11 



Limestone, hard, flinty, Lower Mercer 2 6 



The following fossils were collected: 



Crinoid segments 



Fenestella shumardi Prout ? 



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 boonensis Swallow ? 



Spirifer opimus Hall 



Squamularia perplexa (McChesney) 



Composita subtilita (Hall) 



In eastern Mahoning County the member outcrops in the bed of 

 Yellow Creek, one-half mile east of Poland, forming a projecting ledge 

 over which the water falls. Lamb describes the deposit thus: 1 "The 

 stratum presents here that peculiarity of 2 layers noted elsewhere. 

 The upper layer measured 2 feet 3 inches and the lower 7 inches. Rest- 

 ing directly on the heavy bed is a 2 inch very impure layer of limestone 

 of cone-in-cone structure which breaks easily and shows this peculiar 

 structure quite admirably. The heavy bed is bluish gray, tough, 

 fossiliferous, and sparkles with crinoid stems and calcite crystals. The 

 limestone is directly underlain by black carbonaceous shale which is 

 extremely fossiliferous." The lower bench, however, is much more 

 fossiliferous than the upper. The section here follows (Locality 55): 



, G. F., Pennsylvanian Limestones of Northeastern Ohio below the Lower 

 Kittanning Coal, Ohio Naturalist, Vol. 10, p. 122, March, 1910. 



