MARCELLUS SHALE 
183 
Localities of superposition. 
The following woodcuts illustrate the relative position of this rock in the Fourth District: 
a. Shale of Hamilton group. 
b. Black and olive shale of the Marcellus, gradually passing into that above. 
c. Stratum of limestone with fossils. The shale above and below this limestone is highly fossiliferous. 
d. Black bituminous shale with large septaria. Atrypa limitaris occurs in the lowest layers, resting on the limestone ?. 
e. Corniferous limestone. 
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Section of the bed and bank of Allen’s creelc, at Lc Roy village. 
a. Shale of Hamilton group. 
b. Bluish and dark shales of the Marcellus, 
c. Stratum of limestone, one foot thick. 
d. Black slaty and compact shale with septaria. Bed of creek. 
«. Corniferous limestone, forming the bed of creek as far as the falls. 
