is a 
ace, j 
326 CEMENT MATERIALS AND INDUSTRY. [bull. 243 J 
The limestone outcrops in a belt extending southward from the town. On the 1 
east side is a low ridge of Hudson shale containing graptolites of Utica age near 
the 1 >ase. 1 >ipping at an angle of 20 degrees under these beds are 90 feet of dark, com- 
pact, crystalline and shaly limestones bearing fossils of Trenton age. Below this are 
three or four heavy beds of pure limestone averaging 15 to 20 feet in thickness, with I 
a total of about 80 feet. This is the deposit that is quarried. The upper 'bed 
very massive, compact, light-gray limestone, weathering chalky white on the surface. 
with smooth fracture and but slight indications of bedding. The lower beds are I 
darker, coarser grained, not so homogeneous, and have a rough fracture, and at the 
base are thinner bedded. The only fossils observed in these beds are a few LepM 
ditia found in the upper layers, indicating Lowville (Birdseye) age. 
The whole of this mass is quarried, and is stated to average 98 per cent carbonate 
of lime. The two samples tested by the Geological Survey contained 96.2 and 97.7*; 
per cent. The limestone is quarried in an open cut 200 to 250 feet wide and 80 to 
100 feet deep, the workable depth depending upon the amount of stripping that is j 
profitable. The open cut extends for over 1J miles along the strike and is being 
worked along its entire length. The same beds apparently continue beyond, to then 
south, and there is every reason to believe that they also occur along the strike north 
of the town. The rock is taken out on train cars, is crushed to 5-inch size, and is 
loaded directly into the railway cars on the track. The reason that the stone canjJ 
be profitably shipped such a distance is that the cars which transport the coal from, J 
the Pennsylvania mines to the south return loaded with limestone, thus avoiding an | 
empty return run, and the freight rates are reduced to a minimum. It is reported '| 
that from 20 to 50 carloads a day of the crushed rock are shipped. With a quarry 
face of 80 feet and the dip of the rocks 20 degrees, the estimated output of the quarry 
per mile is about 3,000,000 tons. 
An analysis by Rogers a is given below. It is of a specimen from ail 
point 4 miles from Harpers Ferry, on the road to Martinsburg 
Analysis of limestone from near Harpers Ferry, W. Va. 
Silica (Si0 2 ) 1.83 
Alumina ( A1 2 3 ) 1 
Iron oxide (Fe 2 3 ) / 
Lime carbonate (CaC0 3 ) 95. 86' 
Magnesian carbonate (MgC0 3 ) 1. 46 
LEWISTON (LOWER HELDERBERG) LIMESTONE. 
The Lewiston limestone, although occurring in West Virginia, is noti 
so available a source of cement material as the Trenton and Greenbrier' 
limestones. The only obtainable analysis of rock from this location 
is given below, quoted from Rogers. The specimen anatyzed was 
from Pattersons Creek, near Hampshire Furnace. 
a Geology of the Virginias, p. 170. 
