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Cincinnati Society of Natural History. 



from the underlying Dayton stone, notwithstanding the fact that it is 

 not a shale but a fairly firm stone occurring in layers from 4 to 8 inches 

 thick. Of course in the more south-east counties, where these rocks 

 are exposed, they turn into actual shales, but that is not the question 

 here. I am therefore convinced that the Laurel formation in its 

 complete form as seen in Indiana and western Ohio includes both the 

 Dayton stone and the overlying Niagara shale of more eastern and 

 south-eastern Ohio. 



The Waldron shale overlies the Laurel formation. In my opinion 

 it is paleontologically and stratigraphically slightly earlier than the 

 great mass of rocks usually classed as the dolomitic form of the 

 Niagara. I am not inclined as yet to distinguish the Springfield rock 

 from the Cedarville rock as a separate paleontological horizon. I 

 should call the two rocks a single horizon. The Waldron bed in 

 my point of view represents a bed intermediate between the Laurel 

 formation and this dolomitic form of the Niagara, or rather it really 

 is a sort of transition rock in Indiana. This being the case it is not 

 surprising to find in it species occuring in the Laurel formation at 

 Osgood, and at the same time species, which certainly have close 

 relationship to those found in the dolomitic Niagara in the northern 

 part of the State and in Ohio. Lithologically I should call the. 

 Waldron shale a shaly phase of the upper Laurel bed; stratigraphic- 

 ally and paleontologically, a transition bed towards the dolomitic 

 Niagara. What is meant by calling the Waldron bed lithologically 

 related to the Laurel bed is simply this : the upper part of the 

 Laurel bed is not infrequently more shaly, so that locally it might merge 

 into a series of shales. At the same time it is not a distinct transi- 

 tion lithologically from the purer limestone to a dolomitic limestone. 



35. Richmond. — Going from Richmond about two and a half 

 miles northeastward in the direction of Middleborough, to the bridge 

 across the Middle Fork, the Clinton is found exposed in the form of 

 great "slabs, let down by the gradual decay of - the Silurian rocks 

 beneath to lower and irregular levels. The Lower Silurian limestone 

 is found at its original level on the west side of the road south of the 

 bridge. The Clinton contains OrtJiis caUigramtiia, of a medium num- 

 ber of plications, Ortliis (Platystrophia) biforata, Strophomcna patenta, 

 Meristella umbonata, Rhinopora verrucosa^ Heliolites subtitbulatus, Hel- 

 iolites mcgastoma 't and Favosites favosus. 



