28 J. L. Campbelli—Silurian Formation in Virginia. 
valley. What now caps House Mountain is about three hun- | 
dred and sixty feet thick, while, at the highest point, it may 
have lost one hundred feet or more of its original height. On 
the Warm Springs Mountain, in Bath County, twenty miles 
farther towards the great Appalachian coal basin, the thickness 
is very perceptibly less. At Panther Gap, two or three miles — 
west of Goshen, where the Chesapeake and Ohio Railroad _ 
asses through Mill Mountain, a very complete section of No. — 
is displayed as a folded and inverted anticlinal—inverted 
towards the northwest so that the higher strata of V, VI and 
VII, seem to underlie IV. 
o. V is in most places, in this part of the Appalachians, a — 
bed of shales and brittle, shaly sandstones. In the upper part — 
the shales predominate and have some thin bands of limestone. 
Valuable iron ores, some of them highly fossiliferous, abound 
in this formation. The development of this group is not — 
extensive where our line of section cuts it. This seems to be 
the only representative we have here of the Clinton and — 
Niagara epochs (5d, and 5c, Dan 
a). 
No. VI is not actually visible where the section passes, but — 
in some of its beds to make good lime, and firm enough to- 
make good building material for houses, railroad masonry, 
etc. In the prolongation of the same mountain valley, in — 
which our section terminates, this formation is largely devel- _ 
oped along the line of the Chesapeake and Ohio Railroad, be- _ 
tween Goshen and Buffalo Gap. At Craigsville, nine miles 
northeast of Goshen, it affords an extensive quarry of beautiful 
encrinal marble. It is the Helderberg Limestone. (7 Dana.) 
No. VII is a singular bed of brownish and greenish-gray 
sandstone of coarse texture, easily broken, and in many places _ 
disintegrates readily under the weather. In other localities it _ 
is more durable, forms rather low flat arches, and when cut 
through by streams presents precipitous exposures. It is said _ 
to have valuable deposits of iron ore at several points in Vir- 
ginia. Great numbers of fossil brachiopods, especially Spiryer 
arenosus 
and Rensseleria ovoides, are found in it everywhere. 
This is a remarkably well defined formation, readily distin- 
guished by its lithological peculiarities and its fossil remains. 
It is cut by the Chesapeake and Ohio Railroad at several places __ 
between Buffalo Gap and Goshen. On the turnpike leading _ 
eo 
2 
faa 
