A. M. Miller — Ordovician Cynthiana Formation. 657 



Gastropods 



Bellerophon sp. ?, Cyclonema varicosicm Hall (very character- 

 istic of the formation), Cyclora minuta Hall, Ilormotoma 

 gracilis Hall, Lophospira sumnerensis (?) Saf. 

 Cephalopods 



Orthoceras sp. ? 

 Trilobites 

 Isotelvs sp. ? 

 Calymmene senaria ? Conrad. 



As has been noted by Niekles and others, the foregoing' 

 assemblage of fossils strongly resembles the Fairmonnt fauna 

 of the Mayville, though the species are mostly different. It is 

 quite different from that of the intervening Eden. 



By far the most characteristic single fossil of the Cynthiana 

 is Cyclonema varicomm. It is an easily recognized fossil and 

 present in every extensive exposure of the formation. 



In New York and Canada the Utica shale follows the Tren- 

 ton limestone abruptly with every evidence in those regions of 

 an unrecorded time interval between. 



It is the view of the writer that the Cynthiana partially fills 

 this hiatus southward and that though necessarily transitional 

 in its faunal aspects, it belongs more on the Cincinnatian than 

 on the Mohawkian side of the line. 



A revised table of formation for the Ordovician in Kentucky 

 is here appended. 



Note. — Since preparing the above for publication the writer 

 has received a letter from Professor Ulrich, in which he gives 

 an account of a recent examination of the Cynthiana north- 

 ward from Lair Station to Claysville on the Licking River. 



In this he correlates the lowest layers on the Licking at 

 Claysville with these lowest layers on the Ohio River at Carn- 

 town and Foster and places these not in the Wilmore, but in 

 the lower Cynthiana. With the identification of these beds as 

 Cynthiana the writer cannot concur. 



University of Kentucky, 

 Lexington, Ky. 



