NOMENCLATURE OF THE OHIO FORMATIONS 54 I 



base of the Columbus limestone, or the base of the formation 

 which Dr. Lane in Michigan has named the "Dundee lime- 

 stone.^ The middle member is the Sylvania sandstone of Dr. 

 Orton which was called the " Oriskany sandstone" on the 

 geological maps of Lucas and Wood counties. The rocks below 

 the sandstone are shown at various localities on both banks of 

 the Maumee River from the vicinity of the Providence-Water- 

 ville township line, Lucas county, to Maumee. Provisionally 

 this member is termed the "Tymochtee," a name given in 1873 

 by Professor N. H. Winchell to the thin-bedded Waterlime 

 exposed on the banks of this creek in Crawford township, 

 Wyandot county.^ The limits* of the "Tymochtee slate" 

 were not definitely fixed by Winchell, and further investigation 

 may render it inadvisable to retain this name. Professor Win- 

 chell, however, used it for the thin- bedded Waterlime in several 

 of the northwestern counties, and compared the beds of this 

 character in Wood county with it. 3 



21. In the New York classification this division has been 

 abandoned, and the two older ones of "Rochester shale" and 

 "Lockport limestone" accepted as formations; the former rep- 

 resenting the lower, and the latter the upper part of the old 

 "Niagara group." At present we are unable to correlate pre- 

 cisely the Ohio rocks with these two eastern formations ; there- 

 fore the more gfeneral term of "Niagara," which has been used 

 for this mass of rocks in Ohio, is retained for the time being. 



22. The following subdivisions of the " Niagara group " have 

 been recognized and defined in southwestern Ohio; but whether 

 these shall be considered as formations or subformations, or part 

 of them be grouped together to form new formations, we are not 

 prepared to state at present. It does not appear probable that 

 all of these divisions can be recognized in northern Ohio. 



23. Dr. Aug. F. Foerste has stated that the Niagara shale of 

 the Ohio reports "evidently corresponds stratigraphically to the 



'Mich. Geol. Surv., Kept. State Board for iSgi and iSgi (1893), p. 66; Geol. 

 Surv. Mich., Vol. V, Part II (1895), P- 25; and Sherzer, ibid.. Vol. VII, Part I 

 (1900), p. 35. 



''Rept. Geol. Surv. Ohio, Vol. I, Part I, p. 633. '^ Ibid., Vol. II, Part I, p. 375. 



