72 
SLATE DEPOSITS AND INDUSTRY OF UNITED STATES. 
northeast of Middle Granville, also in Granville; and 39 is 2| miles west of Janes- 
ville, in Whitehall. 
Quarry number. 
Bedding. 
Cleavage. 
Strike joints. 
Strike. 
Dip. 
Strike. 
Dip. 
Strike. 
Dip. 
33 
N. 
N. 
N.+ 
N. 20° W. 
N. 12° W. 
N. 10° W. 
N. 5° E. 
N. 
N. 
N. 15° W. 
N. 30° W. 
30 ± E. 
45° E. 
15° E. 
E.-W. 
35° E, 
25° E. 
50° E. 
35° E. 
30° E. 
22° E. 
20° E. 
34 
35 
N. 15° E. 
N. 5° E. 
N. 12° W. 
N. 5° W. 
N. 5° W. 
N. 
N. 
N. 
N. 15° W. 
20° E. 
30° E. 
35° E. 
30° E. 
45° E. 
40° E. 
40° E. 
25° E. 
25° E. 
36 
N.+ 
55° E. ] 
37 
38 
N. 10° W. 
25° E. ] 
39 
40 
J 
41 
N. 15° W. 
50° E. ] 
64 
66 
Quarry number. 
Dip joints. 
Diagonal joints. 
Grain 
strike. 
Shear zones. 
" Hogbaeks." 
Strike. 
Dip. 
Strike. 
Dip. 
Strike. 
Dip. 1 
33 
N.30°E. 
70° W. 
34 
N. 65° W. 
90° 
35 
36 
E.-W. 
90° 
37 
3H 
N. 75° W. 
90° 
39 
40 
N. 7°E. 
77° E. 
41 
N. 77° E. 
90° 
64 
66 
N. 80° W. 
90° 
N. 55°W. 
70° NE. 
DESCRIPTIONS OF THE SLATES. 
Red slate. — The "red" slate is a decidedly reddish brown, becoming brighter 
exposure. To the unaided eye its texture is fine, and its cleavage surface vari 
from slightly roughish to speckled with minute protuberances ("eyes" or "knots' 
in either case without luster. It is magnetitic, sometimes effervesces with cold dilut 
HC1, is sonorous, and has an argillaceous odor. Under the microscope shows a matrh 
of muscovite (sericite) with somewhat faint aggregate polarization, but this faintness 
is partly due to obscuration by carbonate and hematite, many of the plates of the- 
former remaining light when all the mica is dark and the hematite darkening the mica J 
when it is light. Distributed throughout the matrix are multitudinous bright-red 
hematite dots of circular or irregular oval outline, measuring from 0.0004 to 0.009 mm. 
There is much irregularity in the size of the particles, indicating but a fair grade of 
fissility. The larger particles consist of quartz fragments up to 0.06 by 0.03, rai 
grains of plagioclase feldspar and of zircon, considerable carbonate in rhombs or plat 
up to 0.047 mm., scales of chlorite interleaved with muscovite, up to 0.075 by 0.02 
mm., a very variable number of lenses up to 0.34 by 0.15, rarely 0.5 mm. long, coi 
sisting probably of rhodochrosite (carb. manganese) and chalcedonic quartz (contaii 
ing carbonate rhombs and muscovite scales, sometimes partial pseudomorphs 
chlorite after carbonate), and finally some tourmaline prisms up to 0.005 by 0.001 mi 
The chief constituents of the red slate, arranged in descending order of abuEJ 
ance, appear to be muscovite (sericite), quartz, hematite, kaolin, carbonate, chlorit 
magnetite, rhodochrosite. For colored lithographs of magnified thin sections of tl 
