HURON AND CLEVELAND SHALES OF NORTHERN OHIO 361 
CONCLUSIONS 
It has been shown in Bulletin 15 of the Geological Survey of 
Ohio that the Cleveland shale in the Cleveland region is underlaid 
by the Chagrin and overlaid by the Bedford formation. The upper 
part of the Chagrin formation in the Cuyahoga Valley and to the 
eastward contains a marine molluscan fauna concerning the age 
of which there appears to be a general agreement that it represents 
Fic. 8.—Cleveland shale at junction of East Branch and West Branch of Rocky 
River at Olmsted. 
the Chemung of southern New York which belongs in the upper 
Devonian. The basal part of the Bedford formation also contains 
a marine molluscan fauna which has been found as far west as 
both sides of the Vermilion River and is also present in central 
Ohio. The weight of evidence also appears to support the reference 
of this fauna to the Devonian which has been effectively presented 
in a recent paper by Dr. Girty.* 
In Bulletin 15 in connection with the present paper, it is shown 
t Annals New York Academy of Sciences, XXI, 205-310. 
