DELAWAKE COUNTY. 283 



outcrops on the west side of the Olentangy, but that stream lies, almost 

 without exception, along the western edge of the black slate or of the 

 shale underlying. Alum Creek, and. nearly all of its small tributaries, 

 afford frequent sections of the Huron shale ; but they are so unconnected, 

 and have so great a resemblance one to the other, that they can not be 

 correlated. Hence no correct statement of the thickness of this shale 

 can be given. It has been estimated at about 300 feet. 



It would be impossible to mention every point at which this shale is 

 exposed in Delaware county; hence only those outcrops will be noted at 

 which some features are disclosed which throw light on the general 

 character of the formation. 



In the bank of the East Branch of the Olentangy, near the center of 

 section 1, Marlborough township, at Kline's factory, the following section, 

 in descending order, was taken. It belongs to the lowest part of the 

 Huron : 



Section at Kline's Factory. 



No. 1. Thin, bituminous and brittle, similar to the exposure at 



Cardington, Morrow county 7 ft. 



" 2. Blue shale ; calcareous, hard and compact, parting con- 

 choidally ; less hard and enduring than limestone ; con- 

 cretionary, irregular and bilging ; seen in the bed of the 

 river ; this may not be a constant layer ; seen 6 in. 



Total 7 " 6 " 



Thirty or forty rods below the bridge over the Olentangy, just below 

 the union of the East and West Branches, Troy township, the same hori- 

 zon is exposed in the left bank of the river, on Jos. Cole's land, covering, 

 however, more of both numbers, as follows : 



Section in Huron Shale on Jos. Cole's Land, Teoy Township. 



No. 1 . Black slate, the weathered surface of which is divided 

 into very thin beds ; includes two beds, of an inch or 

 two each, of less bituminous shale, which is blue, if 



damp, but brown when dry and rusted 23 ft. 



" 2. Blue shale, yet in regular, thin bedding 6 in. 



" 3. Same as No. 1 4 " 



" 4. Bluish or purplish shale, in thin beds 3" 6 •' 



" 5. Black slate : 8 " 



" 6. Massive blue shale, weathering out superficially in small 

 rounded pieces or short cylinders, the upper ends of 

 which are convex and the lower concave, the equiva- 

 lent of No. 2 at Kline's.factory 1" 3 " 



" 7. Blue bedded shale ; seen 3 " 



Total 32 " 6 " 



