580 P, E. RAYMOND TRENTON OF TENNESSEE AND KENTUCKY 



of the Blue Grass area in Kentucky, where the Perryville intervenes be- 

 tween the Woodburn and Catheys, the Trenton succession is obviously 

 broken, and at about this place new elements enter the fauna and some 

 of the old ones disappear. One of the most striking things noted is a sort 

 of quickening of evolutionary processes, as though the species had long 

 been dormant and now began to change. This is seen especially in cer- 

 tain of the brachiopods. The Platystrophias of the Curdsville, Hermi- 

 tage, Bigby, Benson, and Woodburn are all small things, more or less 

 alike, but in both the Catheys and Cynthiana they increase in size, till at 

 the top some specimens are nearly as large as any in the later Ordovician. 

 The little Hebertella franJcfortensis is replaced by H. maria parJcensis, 

 some specimens of which can hardly be distinguished from H. sinuata. 

 Rliynchotrema increbescens gives way to Orthorhynchula linneyi, which, 

 starting in the Salvisa with a small form, increases in size throughout 

 the Cynthiana, Catheys, and Leipers. 



As compared with deposits in New York and Ontario, there is abso- 

 lutely nothing in common which has any weight in correlation. This is 

 explained by the fact that the Upper Trenton was a time of uplift and 

 deposition of shale in New York. Kentucky and Tennessee also felt the 

 effects of uplift at this time, as already shown, but they were too far from 

 the land to be affected at first by the clastic material which destroyed 

 much of the Trenton fauna in New York and brought about the "Utica" 

 fades. The uplift which affected that part of Kentucky occupied by 

 deposits of the Perryville seems to have been followed by a slight deepen- 

 ing of the -waters during Cynthiana times, so that lagoon conditions were 

 replaced by those of shallow seas or banks on which corals, bryozoa, and 

 brachiopods flourished. 



The general effect of the uplift at the east had been to bring the shores 

 appreciably nearer this region and may have diverted to it currents 

 carrying an augmented food supply, thus causing the "awakening" re- 

 ferred to above. These more favorable conditions did not persist long 

 in Kentucky, however. The mud of the Utica came as near as the Ohio 

 Eiver (Fulton shale) and drove out or killed the Trenton — Cynthiana 

 fauna there. In the section on Glenn Creek at the Old Crow distillery, 

 the bed which shows the second appearance of Cryptolithus is only about 

 35 feet above the base of the Cynthiana, and with the coming of that 

 trilobite the warm water fauna (Cynthiana) disappears from the region. 

 Then follows a long period (Million shale) when there was mud in Cen- 

 tral Kentucky and the fauna was much reduced in variety. 



If one turns now to Tennessee, one finds the Catheys much thicker 

 than the Cynthiana, and, furthermore, the Cynthiana-Catheys fauna per- 



