Seen 
April 21, 1871. 489 
[ Lesley. 
THE GEOLOGICAL STRUCTURE oF TAZEWELL, Russe AND WISE 
COUNTIES, IN VIRGINIA. 
By. J. P. Lesuny. 
(Read before the American Philosophical Society, April 21st, 1871.) 
I was called upon recently to examine a part of the Alleghany Moun- 
tain Range, between the New River (Kanawha) in Middle Virginia and 
the north line of the State of Tennessee, for the purpose of determining 
the nearest possible approach to a workable coal region of a contemplated 
Railway from Harper’s Ferry on the Potomac to Knoxville in Tennessee. 
The geological structure of this part of the United States is so peculiar 
and so nearly unknown to geologists, or at least unnoticed in any pub- 
lished memoirs, that I have taken some pains to portray it, believing that 
it will be an acceptable contribution to the literature of the science and 
to the proceedings of this Society. The present paper is, however, a 
virtual continuation of my description of the South Virginia Coal region 
of Montgomery and Wythe Counties, read before this Society in 1862, 
and published in Vol. IX of its Proceedings, pages 30 to 38. 
Professor William B. Rogers, State Geologist of Virginia, is well 
acquainted, no doubt, with the essential facts about to be described, and 
probably has materials for a more extensive description of the central 
belt of the Appalachians among the unpublished archives of the State 
Geological Survey of Virginia; but I doubt that any sections have been 
constructed which express more clearly the state of things in a geological 
sense, than those which I have this opportunity of making known. 
Professor James M. Safford, State Geologist of Tennessee, has studied 
the Southern continuation of the belt, and describes it in his Geology of 
Tennessee, Nashville, 1869. But the sections given in that valuable work, 
which has cost its author so much time, skill and labor to prepare, and 
for which American Geologists are most grateful, are only adapted for 
general description, not being drawn to a natural scale, and are not of 
use-for the critical study of the dynamic problem here offered to the con- 
sideration of structural geologists. 
The map which accompanies this paper was made to show the railway 
avenues through the region above named, by bringing out clearl y its 
main topographical features. I have colored it to show to the eye its 
main geological features, especially those due to the lines of Downthrow, 
which are also the lines of limit for the Coal Measures. I have confined 
the coloring within narrow limits so as not to obscure the prime facts. 
No distinction is made therefore between the Calciferous, Trenton, Birds- 
eye, Black River and Hudson River formations, all of them being colored 
A. P, §S.—VOL, XII.—3s 
