318 CEMENT MATERIALS AND INDUSTRY. [bull. 2f|p 
CALCAREOUS MARLS. 
:; 
Small deposits of calcareous tufa have been noticed in various pa 
of the valley, and these, if favorably located and sufficiently large 
would undoubtedly be of much value in cement manufacture. 0: 
more importance, however, are the deposits of calcareous fresh-watej 
marl which have been found scattered throughout this region. Ir 
certain portions of Staunton, as has been noted by Mr. Catlett, thf 
foundations of houses are cut in marl 10 to 12 feet deep. The surface 
indications of these marls are usually so meager that no estimate o 
their quantity or extent can be determined from these alone. 
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DETAILS OF LOCALITIES. 
An exploration starting at Woodstock, in the northernmost part oi 
the valley visited, and ending in the vicinity of Natural Bridge, disM b 
closed the more favorable localities showing good exposures of thlij 
argillaceous limestone, which are briefly discussed below. In indicating 4 
advantageous sites for cement plants, the writer means to imply simply] 
that the cement rock and pure lime deposits occur at the places men j 
tioned and that the transportation and other necessary facilities are I 
hand. Whether a good cement can be made from the raw materials 
found at these places is a matter which can be determined only by; 
experimentation on a commercial scale. The argillaceous limestone > 
in most instances have a composition very similar to good cemen 
materials of other regions, but this does not necessarily indicate th 
they also will make a first-class cement. 
Woodstock and vicinity. — About 350 feet of argillaceous Trentoil pi 
limestones are exposed just east of Woodstock, the town itself being] 
situated upon cherty limestones of Beekmantown age. These lime- la 
stones and the overlying shales dip southeastward at an angle of about i; ii 
45°. and lie on the outcrops of the western edge of the great synclinelsi 
forming Massanutten Mountain. Practically the same thickness oi |§ 
cement rock is exposed northeast and southwest of Woodstock. As 
this line of outcrop is paralleled by the Southern Railroad, which is atu 
no place more than 3 miles distant, numerous sites favorable fori 
cement plants are available. The most prominent location, however/, 
is the immediate vicinity of Woodstock, since here the cement rocks I 
outcrop on the western side of the North Fork of the Shenandoah! 
River. Farther south the river flows between the railroad and the> 
line of cement rock outcrop and would thus greatly increase the cost! 
of a spur line. 
Pure limestone for mixture with the cement rock can be found inn 
the immediate vicinity, more probably in greatest quantity just west*( 
of the town. Limestone strata, high in calcium carbonate and low inn 
magnesia, were found interbedded with the dolomites west of Wood- 
