Virginia and the Southern Appalachians. 55 



found in the Appalachian region south of ]New York. In the 

 central eastern Tennessee section the upper limit of the Mid- 

 dle Cambrian fauna is in a shaly band, not fifty feet below the 

 cherty beds of the Knox dolomites which usually have been 

 referred to the Lower Silurian (Ordovician). The recent dis- 

 covery by Mr. M. R. Campbell of the typical Calciferous fauna 

 of the New York section at an horizon 2000 feet up from the 

 base of the dolomites negatives this reference and indicates 

 that the Upper Cambrian in Tennessee is represented by the 

 lower 2000 feet of the Knox dolomites in the southern por- 

 tion of the Appalachian trough. In the vicinity of Rutland, 

 Vermont, the upper portion of the Lower Cambrian and all of 

 the Middle and Upper Cambrian, if present, are included in 

 the dolomites and marbles above the " granular quartzite " and 

 it is probable that the lower portion of the great limestone 

 belt of Pennsylvania and Virginia is of Cambrian age. 



The sediments of the massive quartzites of the Lower Cam- 

 brian that extend from Northern Vermont to Alabama, along 

 the line of the eastern margin of the Cambrian paleo-Appa 

 lachian sea were evidently accumulated near the shore. At 

 Balcony Falls, Virginia and Chilhowee Mountain,* Tennessee, 

 the Olenellus fauna occurs in connection with the series, and 

 it appears to be a fair inference that while the sandstones of 

 Chilhowee, etc., were being deposited in the vicinity of the 

 shore line the variegated shales and limestones of the Lower 

 Cambrian were being deposited farther off shore in the sea to 

 the west. This sea was shallow and from the distribution of 

 the Rome sandstone series the inference is that much of the 

 sediment was derived from the west. The close of the epoch 

 in which the Coarse sand was deposited along the Virginia 

 portion of the shore was abrupt and the immediately super- 

 jacent deposits indicate a deepening of the sea. The Rome 

 sandstone epoch was of relatively short duration although of 

 wide geographic distribution in eastern Tennessee and northern 

 Georgia and Alabama. 



The conditions which resulted in the deposition of the 

 Knox dolomites during Upper Cambrian time in the southern 

 portion of the Appalachian trough were probably connected 

 with the orographic movement that gave rise to the more strik- 

 ing phenomena in the northern portion of the Appalachian 

 trough, and affected the deposition of the sediments over the 

 interior of the continent. 



In the valley of the St. Lawrence, especially at Point Levis, 

 opposite Quebec, a bed of conglomerate occurs on the south 

 shore of the St. Lawrence below Point Levis and also on the 

 south shore of the Island of Orleans. This conglomerate 



*Bull. U. S. Geol. Survey, No. 81, 1891. p. 302. 



