652 A. M. Miller — Orclovician Cynthiana Formation. 



nessee (to which in part it belongs), but subsequently corrected 

 this in the proof to " Winchester." However, a section on 

 page 21 and the map accompanying the report had at that 

 time already been engraved and retains the name " Catheys." 

 In the report, however, the name Cynthiana was limited to 

 those lower "rubbly" limestones of Linney's Lower Hudson 

 which in the area under discussion attained a thickness of 40-60 

 feet. 



The reason for including under the name "Winchester" 

 less than was embraced by Linney or Campbell under that 

 name was the result of investigations carried on by the writer 

 alone, and also in conjunction with Foerste and Nickles, which 

 led to the tracing of these beds northward to the Ohio River 

 at Cincinnati and Moscow and to the discovery that the Eden 

 of Orton included the upper portion of the Winchester beds. 

 The first placing of the Winchester in the Cincinnatian was in 

 the publication by J. M. Nickles entitled The Upper 

 Ordovician Rocks of Kentucky and their Bryozoa.* Subse- 

 quently, Foerste, in the " Table of Paleozoic Formation " for 

 Kentucky in his Silurian, Devonian and Irvine Formations 

 of East-Central Kentucky,f showed the true equivalence of 

 Winchester and used the name " Cynthiana " for that portion 

 of it lying below the Eden or below the Fulton bed at Ludlow 

 which had been provisionally correlated with the Utica of 

 New York. He divided the Cynthiana in ascending order into 

 the Greendale and Point Pleasant. 



The writer of the present paper, finding practically every- 

 where in North Central Kentucky towards the top of the 

 Cynthiana, wave-marked crinoidal limestone layers made up 

 of the stem plates and occasionally of portions of the calyces 

 of the crinoid Ectenocrimis simplex, also fragments of the shells 

 of the brachiopod Plectambonites rugosus James (sericeus of 

 Meek, not Hall) and of the trilobite, Trinucleus concentric a*, 

 drew the line between the Cynthiana and Eden at the base of 

 these crinoidal layers. About ten feet above the base of these 

 layers perfect shells of Plectambonites rugosvs become abundant 

 and range through the remainder of the Eden ; Ecteno- 

 crinus simplex has the same range. The shaly character 

 of the Eden also becomes apparent at this horizon. It 

 was the presence of these shales which makes appropriate 

 Orton's name '" Eden Shales." A recent joint examination in 

 the field by E. O. Cinch and the writer has disclosed that 

 the former has been drawing the line between the Cynthiana 

 and the Eden at this horizon, about 10 feet above where the 

 writer has been drawing it, and further that along the river 

 front in the old Fulton Ward of Cincinnati the bed of clay 

 *Ky. Geol. Surv., 1905. fKy. Geol. Surv., 1906. 



