112 SLATE DEPOSITS AND INDUSTRY OF UNITED STATES. 
bedded here and there with a few inches of slate consisting of muscovite (sericite), 
quartz, chlorite, and biotite, and containing garnets and lenses of quartz, muscovite, 
and chlorite, some of which are probably altered garnets. The quartzite also has 
slate of this character on both sides of it. On the east the quartzite dipping 80° E., 
is followed conformably by 40 feet of such slate, then by about 300 feet of micaceous 
quartzite, followed by an undetermined thickness of ferruginous slate full of pseudo- 
Scale of miles 
2 
Contour interval 50 feet 
Fig. 12. — Map of slate region in Buckingham and Fluvanna counties, Va, Quarries shown by crossc 
hammers; slate prospect by round dot; strike of commercial slate by arrows; quartzite areas b 
fine dots. 
morphs or crystals of mica (muscovite?) \\ millimeters across, the plates of which li 
across the foliation of the rock. This slate was originally bluish gray, but weather 
a hematite red. 
The general structure of the belt in which the commercial slate beds lie, judgin 
from the railroad cuttings between New Canton and Slate River, appears to eonsie 
of minor folds. It is traversed by numerous dikes of olivine basalt, ranging from 
