REPORT OF THE STATE PALEONTOLOGIST 1901 645 



was deposited at the same time and in great volume along the 

 western side of the Great Valley of east Tennessee by the Missis- 

 sippian sea, from which the bay was separated by the narrow 

 Rome barrier. The Chickamauga limestone embraces in this chicka- 



*^ mauga 



region unmistakable representatives of every important member ^^"^^^*°°® 

 of the sections of middle Tennessee and central Kentucky, rang- 

 ing from the base of the Stones river to lower Lorraine; and the 

 Stones river divisions are particularly characteristic. 



Elevation of the Lenoir basin now (presumably at close of 

 Trenton) took place, bringing in a very different arrangement. 

 The elevation was greatest at the southern end, thus cutting off 

 all communication with the Atlantic. At the same time the 

 middle third of the Valley trough sank, allowing the waters of 

 the Mississippian sea, which, at least from Black river time on, 

 occupied the middle third, to invade southwardly into the former 

 confines of the Lenoir bay. The result of this revolution and 

 invasion is the Bays and Clinch sandstones, and the lower, non- ^.^y^^?'* 



•^ ' ' Clinch inva- 



ferruginous, shale division of the Rockwood formation, all of ^^°° 

 which, as is indicated by fossils collected from the last by M. R. 

 Campbell, of the U. S. geological survey, are of Cincinnatian 

 (perhaps Lorraine) age. Continued elevation of the southern 

 end of the Valley trough is indicated by the fact that of the three 

 formations mentioned the first extends farthest south, the sec- 

 ond not so far, and the third again falling short of the Clinch. 



Before the close of the Ordovicic both the Lenoir bay and the fmil.ge°n"cl 

 Cumberland basin had been raised above sea level. This emer- 

 gence took place about the beginning of the Richmond age, dur- 

 ing which the Mississippian sea was restricted to the Ohio valley 

 and west and south of the Cincinnati line of uplift. Prior to 

 this time, or at the beginning of the Lorraine, which probably 

 corresponds very nearly to the time of the Bays and Clinch in- 

 vasion described in the preceding paragraph, there was another 

 emergence that reduced the Frankfort phase of the Mississippian 

 sea by excluding its waters from the valley of the upper Missis- 

 sippi and from the various basins lying east and south of Rome 

 N. Y. We see, then, that both of these emergences were ac- 



