THE NIAGARAN FORMATIONS OF WESTERN OHIO 339 



Thickness Thickness 



No. Feet Inches Feet Inches 



somewhat impure, and in part of rather light- 

 gray color. This layer varies in thickness from 



1 2 to 13 inches 1 |± 8 n| 



5. Eleven-inch layer 11 7 n 



4. Four-inch layer 4 7 o 



3. Layer from 7 to 8 inches thick 7|± 6 8 



2. Layer from 3 to 4 inches thick and the base of 



the Dayton limestone. The average thickness 



of layers Nos. 2 to 1 5, inclusive, is 9 feet 3 inches 3§± 6 ^ 



The Dayton limestone is correlated by the 



writer with the compact, even-bedded limestone 



below the soft, blue shale or clay of the Osgood 



beds of Indiana, as defined by Dr. Foerste. 



Therefore in this and the following sections of 



this paper the Dayton limestone is regarded 



as the lower member of the Osgood beds. 

 1. Brassfield limestone. — The bottom layer of the 



extreme western wall of this quarry is the upper 



part of the Brassfield limestone. Farther to 



the southeast on this western side of the quarry 



5f feet of the upper Brassfield limestone, from 



its contact with the Dayton limestone to the 



bottom of the quarry, is shown. It is a crystal- 

 line limestone of light-gray to pinkish color, the 



bedding surfaces frequently of greenish color. 



The upper part is fairly fossiliferous, the com- 

 mon forms being corals, Bryozoa, Stromato- 



pora, and crinoid segments. Some of the rock 



contains so many crinoid segments that it is a 



crinoidal limestone. Bottom of this part of 



the quarry 5 9 5 9 



In the foregoing section, Nos. 2 to 21, inclusive, are referred to 

 the Dayton limestone, which then has an average thickness of 11 

 feet 1 inch in the western part of the Smith quarry. Samples of 

 the Dayton limestone from this quarry were analyzed by Professor 

 D. J. Demorest with the following result: 



