044 NBW YORK STATE MISBUM 



llaviiijj: described the Ordovicic conditions that prevailed in 

 Xew York, and the bearing? of the Appahichian barriers in their 

 development, we turn to a briefer discussion of the conditions 

 obtaininj; at the same time in the regions containing the middle 

 and southern thirds of the Valley trough. 



While the Chazy and succeedingOrdovicic deposits were being 



laid down in the north in waters having direct communication 



with the north Atlantic, another series of rocks was in course of 



deposition in a bay separated from the Missis«ippian sea by the 



Rcms barrier Romc iHirrier, which is the sharply defined southern extension of 



and Lenoir , , , , j -i •■« * 



basin the Appalachian valley fold. Tins bay may take the name of 



Lenoir. It communicated with the Atlantic at its southern end 

 and extended northeastward between the Rome and Chilhow^ee 

 barriers from middle-eastern Alabama to southwestern Virginia. 

 Athens and xiie Ijeuoir bay occupied a^ synclinorium containing several 



troughs disconnected longitudinal folds high enough to atfect the direc- 



tion of currents and consequently the character of the sediments 

 and, in a smaller degree, faunal distribution. In a general w^y 

 the deposits may be divided into an eastern (Athens trouffh) 

 and a western series {KnoxviUe trou(/h), the members of 

 which, on account of differential warping and subsidence, 

 and lateral conjunction, overlap or grade into each other 

 along the t^hifting median line. On the eastern side we 

 have the Athens shale and sandstone, which are supposed 

 to correspond with the Lenoir limestone of Safford (in 

 part the same as the Chickamauga limestone of Hayes, 

 CamplM^ll and Keith), and its great lenses of Ilolston marble 

 Correlation occupyiug tlio westem half, (^ompared with the sediments in 

 dcp°osu7!n'' 111,, northern A].pala<;hian troughs (Chazy basin and Levis 

 channel), they probably fill 11h' interval there occupied by the 

 Chazy, Levis and Normans kill shale. The Tellico sandstone and 

 the Moccasin limestone follow, the former in the eastern half, 

 the latter in the western, while the Sevier shale spreads over 

 both sides. The last formation probably is equivalent in time 

 to late Trenton and, possibly, Utica. 



These Lenoir bay deposits contain faunas wholly distinct from 

 those pertaining to the true Chickamauga limestone series, which 



Lenoir basin 



