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NEW YORK STATE MUSEUM 



R 



an 

 basin 



Athens and 



Knoxville 



troughs 



Having described the Ordovicic conditions that prevailed in 

 New York, and the bearing of the Appalachian barriers in their 

 development, we turn to a briefer discussion of the conditions 

 obtaining 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 Mississippian sea by the 



ome barrier Rome barrier, which is the sharply denned southern extension of 



id Lenoir ' x ^ 



the Appalachian valley fold. This bay may take the name of 

 Lenoir. It communicated with the Atlantic at its southern end 

 and extended northeastward between the Rome and Chilhowee 

 barriers from middle-eastern Alabama to southwestern Virginia. 



The Lenoir bay occupied a synclinorium containing several 

 disconnected longitudinal folds high enough to affect the direc- 

 tion of currents and consequently the character of the sediments 

 and, in a smaller degree, fauna! distribution. In a general way 

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

 and a western series (Knoxville trough), the members of 

 which, on account of differential warping and subsidence, 

 and lateral conjunction, overlap or grade into each other 

 along the shifting 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, 

 Campbell and Keith), and its great lenses of Holston marble 

 occupying the western half. Compared with the sediments in 

 the northern Appalachian troughs (Chazy basin and Levis 

 channel), they probably fill the 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 



Correlation 

 of Ordovicic 

 deposits in 

 Lenoir basin 



