Remarks on the Coal Formation of Pennsylvania. 345 
Shaver’s mountain by day light, I am able to say that its structure re- 
sembles that of the Savage to near its top. Bape ge 
The location of the road reflects great credit on the engineers ; 
the contour is admirable, and must be highly valued by geologists, 
as it presents a profile section across the whole range, clinging on one 
side to the mountains, that, in some places, seem to tower miles above 
and so near walls, formed by the cut, that the carriage wheels often 
graze them; and on the other, a precipice almost perpendicular, 
leading to a gulf below that the eye cannot fathom. e sand- 
stone strata which are almost constantly insight from the base of 
Shavers to near the greatest altitude of the Savage, incline 15° or 
20°, as well as I could judge in passing rapidly—the dip opposite the 
setting sun in the middle of November. From thence it declines by — 
gradations hardly perceptible to near the western base, and there be- 
comes horizontal, like all the strata far beyond the Ohio. 
There are several varieties of sandstone ; the most common has a 
yellow or ferruginous tinge,—the layers are of sufficient thickness for 
all the masonry on the whole line of road, and for this purpose it 
has been used in the numerous bridges, culverts and embankments, 
which are constructed with skill; but the cement has entirely failed, 
owing probably to substituting Zoam for sand, which appears to be rare 
in these regions ; I have never been able to discover a pebble, or a 
handful of silex except in the beds of water courses, or that which 
is coherent in the sandstone, on any of these mountains,—the soil 
being a fine friable loam. The parapet walls of all these construc- 
tions exhibit a mortifying appearance of dilapidation, they are all fast 
crumbling, some already even with the pavement, and fatal accidents 
may soon be expected to follow. 
In many cuts on the Savage, the sides next the mountains present 
4 mural front Matacic, in layers resembling regular masonry 5 
reminding one of those walls described by Lewis and Clarke on their 
toute to the Rocky Mountains, although upon a much smaller scale. 
On the principal elevation, I observed extensive patches of the surface 
Upon the supposition that the sandstone is siliceous, of which the observations of Mr, 
Pomeroy can leave no doubt; as silex is indispensable in mortar, it moni justify, in 
case, even a heavy penditure int porting d and gravel, 
Provided it can be obtained in no other way —Ed. 
45 
Von, XXI.—No. 2. 
