Lesley.] 32 [May. 



very unusual arrangement of the head waters of the Tennessee River, 

 in long parallel branches, with few subordinate affluents, suddenly 

 uniting through mountain gorges, or at the ends of long mountains. 



In each pair of PalDeozoic mountains the eastern one carries a coal 

 area on its seaward flank ; because, the last formation to dip against 

 each fault is the Coal at the top of the series, abutting against the 

 Lower Silurian of the limestone valley which always exists on the 

 eastern side of the fault; as seen in the accompanying diagram, re- 

 presenting a section made across three pairs of mountains just north 

 of Wythe. (See Fig. A.) 



The coal here represented, however, is not the coal of the Carbo- 

 niferous formation, commonly so called. 



Underneath the true coal measures of Pennsylvania, Ohio, and 

 Northwestern Virginia, and underneath the Millstone Grit Conglo- 

 merate (No. XII) at its base, and the Pied Shale formation (No. XI), 

 which underlies the last, there begins, even in Pennsylvania, to ap- 

 pear an older coal formation, connected with the uppermost Devonian, 

 white, mountain Sandstone, No. X. It is seen in one or two beds 

 two feet thick at the head waters of the Juniata. It is mined where 

 the Monongahela waters cut through Chestnut Ridge from Virginia 

 into Western Pennsylvania. It has been mined in the mountains on 

 the Potomac hdow Cumberland. It appears occasionally in Northern 

 Middle Virginia, on the western side of the Great Valley of Win- 

 chester. It increases in importance along the western outcrop of the 

 great coal field through Eastern Kentucky, until it enters Tennessee. 

 It seems, however, to attain its maximum development in Montgo- 

 mery county, on the New River, in Southern Virginia, near the line 

 of our section. Here it is seen to consist of two principal coal-beds 

 and several minor seams. The lowest bed reaches the thickness of 

 four feet, and the next one above it is in some places nine feet thick. 

 In the Peak Hills, just east of Wythe, along the line of the railroad, 

 numerous lenticular deposits of coal are seen, and thin distorted beds, 

 the whole composing a formation several hundred feet thick. Near the 

 New River, the two beds above-mentioned are seen to be covered by 

 at least a thousand feet of Red shale; upon which rests a Subcarbc- 

 niferous limestone ; w^hich abuts, at the foult, against other limestones 

 belonging to the Lower Silurian age. Between Christiansburg and 

 Blacktown, north of New River, a regular synclinal coal-basin has been 

 preserved for a few miles upon the eastern side of the great fault, 

 which crosses the river in front of the gap. In this coal-basin the 

 two beds of coal are preserved, but in a crushed condition. To the 

 southwest, two faults cut off a similar .short basin from the regular 



