REPORT OF THE STATE PALEONTOLOGIST 1002 



1025 



shales and 

 flags 



4tf 



black shale 



feet and the second 56 feet above the base of this section. 

 These beds are equivalent to the upper part of Hatch flags and 

 shales of eastern sections. 



Dunkirk shale. A third black band, the Dunkirk shale, similar 

 in character to the Middlesex and the Rhinestreet shales, succeeds 

 the 112 feet of lighter beds and is 55 feet 

 thick. At the bottom there are 35 feet of 

 densely black, slaty shales, like those in 

 the other black bands and containing the 

 same species of Lingula. 



The base of this shale is exposed in the 

 cliffs on the south side of Dunkirk harbor 

 and in the escarpments on the west side 

 of Point Gratiot. The septaria are strewn 

 along the beach 2 miles southwest in the 

 vicinity of Van Buren point. 



The same beds are exposed in the bot- 

 tom and sides of Silver creek under the 

 high bridge at Hanover Center and in two 

 large ravines near North Collins, and 

 along the highway on the hill 1 mile east 

 of Eden Center in Erie countv. 



Above the Dunkirk shale light, soft 

 shales again predominate, but layers of 

 black shale from an inch to several feet in 

 thickness occur very frequently, and con- 

 cretions are common. 



A row of very large septaria 148 feet 

 above the black band in the Walnut creek 

 section appears on the lake shore opposite 

 Brocton. A sandstone 4 inches thick lies 

 just above the septaria and flags, and thin 

 sandstones increase in numbers and thickness above this hori- 

 zon. They are very rare below it. A band of soft shales 67 

 feet thick, in which there are a few flags but concretions are 

 almost entirely absent, is succeeded by a band of similar shales 

 and flags 25 feet thick in which there are several rows of 

 concretions. 



light shale 



black shale 



light shale 



dark and 

 light shale 



Fig. 11 Section on Wal- 

 nut creek from Silver Creek 

 village to Keech 's Corners. 

 Station 55 



