77;(' Ciiif i>i nulla H Series and its Brachiopods. 41 



time. This peneplain which was only partial in the moun- 

 tain regions, was almost completed over vast areas of the. 

 interior of the continent. At this time the area at Cin- 

 cinnati was peneplained. This Tertiary peneplain is rep- 

 resented by the level crests of the hills about Cincinnati. 

 Upon this plain, stood a few low-lying monadnocks, which 

 now show a ver}' low swells above the flat-topped uplands. 

 The Tertiary peneplain was uplifted, and then began the 

 development of the present topography of the region. At 

 the beginning of the Pleistocene period, most of the present 

 stream valleys were formed, and the topography was similar 

 to that of today. During the Glacial Epoch the topography 

 was modified by changes in drainage, by the deposition of 

 till, and by outwash deposits. Post-Pleistocene erosion has 

 completed the development of the existing topographic 

 features. 



IV. History of the Nomenclature 



Early in the nineteenth century, the "Blue Limestone" 

 as the Cincinnatian series was then called, became well 

 known because of its wonderfully abundant fauna. Many 

 attempts have been made to correlate it with the formations 

 of the eastern states, resulting in the application, at different 

 times, of various riames. At one time it was considered by 

 James Hall to be the equivalent of the Trenton of New 

 York (including Trenton, Hudson River, and Utica slate), 

 and throughout Volume I of the New York Paleontology, 

 reference is made to the Cincinnatian series as the "Trenton 

 limestone." Nickles, in 1903, in his paper, "The Geology 

 of Cincinnati"^ gave a concise and adequate account of the 

 history of the nomenclature up to that time. At that time, 

 the names Utica and Lorraine were accepted terms. Later 

 investigations have shown that the Utica of New York is 

 represented by only the basal five feet of the formation 

 formerly called Utica at Cincinnati. To this five feet the 



♦Campbell, Richmond Folio (No. 46); Fenneman, U. S. Geol. Surv., bull. 348, p. 43. 

 tNickles: Jour. Gin. Soc. Nat. Hist., vol. 20, 1902. p. 52. 



