THE NIAGARAN FORMATIONS OF WESTERN OHIO 345 



basal part of the Niagaran series of that state. As early as 1896 

 Dr. Foerste stated that — 



The identity between the Clinton faunae of the two states [Ohio and New 

 York] on closer examination is not found to be so close as at first supposed. 

 Whether this is due to geographical causes, the Clinton of New York being 

 more literal, or whether it is due to moderate differences of horizon, can not be 

 told until the Clinton of New York is much more closely studied. Although 

 I have been accustomed to call the Ohio formation the Clinton, yet I should 

 be willing to recognize the fact that the identity is not very marked, by giving 

 it a name of its own, for instance, the Montgomery formation, on account of its 

 typical development in Montgomery County, in Ohio. 1 



In 1906 Dr. Foerste proposed the name Brassfield formation for 

 this limestone from outcrops "along the Louisville and Atlantic 

 Railroad, between Brassfield and Panola, in Madison County," 

 Kentucky. 2 It was stated that "for the .... limestone section 

 at the base of the Niagaran division of the Silurian, hitherto identi- 

 fied with the Clinton of New York, the name Brassfield limestone 

 is proposed." 3 



After listing the fauna of the Brassfield limestone in Kentucky, 

 Ohio, and Indiana, and noting the absence in it of certain charac- 

 teristic Brachiopods of the New York Clinton, Dr. Foerste wrote 

 as follows: 



The identification of the Brassfield limestone of Kentucky, and of its 

 northern extension in Ohio and Indiana, in former years, with the Clinton 

 limestone of New York, rests rather upon a somewhat similar facies of 

 the two faunas, and upon the general absence of the more typical species of 

 the Rochester shale fauna of New York in these limestones at the base of the 

 Silurian in Ohio, Indiana, and Kentucky, than upon the presence of any con- 

 siderable number of species common to both areas. On closer inspection, the 

 fauna of the Brassfield limestone of Ohio, Indiana, and Kentucky appears to 

 differ sufficiently from the fauna of the Clinton limestone of New York to 

 warrant the assumption of the presence of some sort of barrier between these 

 two areas. 4 



Dr. Foerste has also stated in a later publication that "the 

 Brassfield limestone is the southern continuation of the strata 

 which were identified in Ohio, by Professor Orton, as Clinton. " s 



1 Journal of the Cincinnati Society of Natural History, XVIII, 189. 



2 Kentucky Geological Survey, Bull. 7, p. 27. 3 Ibid., p. 18. 4 Ibid., p. 35. 



s Journal of the Cincinnati Society of Natural History, XXI (September, 1909), 1. 



