150 
INDEX. 
Tage. 
Cleavage bands, occurrence of 31-32 
plate showing 64 
slipping of, figures showing 32 
Cocke, C. C, slate deposits of 115 
Color of slates, causes of 7, 39-42 
changes in 46 
shades of 5 
Compass, use of, in prospecting 44 
Coons, A. T., on slate production 125-132 
Corrodibility, tests of 48 
Credner, G. R.,on rutile in slates 13 
Crosby, W. 0.,on Brownville slates 66 
1). 
Danville, slate deposits of 52 
Daubree, A., experiments of 8,25 
De iaBeche, H. T.,on cleavage of slates — 24 
De la Harpe and Reverdin. on porosity of 
-late 48 
Density of slate, testing of 47 
Dikes, occurrence of, in slate 33 
relation of joints and shear zones to... 28, II 
Discolorati< »n, cause of > 15-17, 39-42 
effect of, on values 46 
occurrence of 6, 12, 16 
Donald and Campbell, on slate character- 
istics 17 
E. 
East Bangor Consolidated Slate Co., slate 
quarries of 77-78 
East Brownville Slate Co., slate of 66 
East Poultney, Vt., slate deposits near 31 
Eckel, E. ( '., on Arkansas slates 51-53 
on Cah torn la slates 56 59 
on Georgia slates 59-60 
on Tennessee slates 88-89 
on Utah slates 89 
Elasticity, character of 47 
Em pile Red Slate Co., slates of 16 
England, slates of, analyses of 18,34-35 
slates of, cleavage in 23 
Epidote in slate, occurrence of 11 
Eureka quarry. Pa., structure in, figure 
showing 83 
view in 82 
Eureka Slate Co., quarry and slate ot 5(1-58 
Exports of slate, table showing 133-137 
F. 
Fair Haven. Vt., shear /one at, plate show- 
ing 30 
slate quarries near 101 
slip cleavage at, plate showing 26 
Fair Haven Red Slate Co., slates of 19 
slates of, bedding of, plate showing 20 
False cleavage. See Slip cleavage. 
Faults, occurrence of 29 
Feldspar in slate, occurrence of 11, 14 
Fissility, definition of 25 
occurrence of 5-6 
See also Slip cleavage. 
Flints, definition of 32 
nature and cause of 43-44 
occurrence of 32-33 
See also Veins, quartz. 
Folds, axes of, relations of cleavage and... 23 
effects of 7-8 
Page. 
Fontaine quarry. See Pitts, A. L. 
Forks, Me., slate deposits at 67 
Fracture, character of 45-46 
Fracture cleavage. See Slip cleavage. 
France, slates ot 6 
slates of, analyses of 34-35 
Fresenius, R., on slate 48 
Frost, effect of, on slate 24 
Garnet in slate, occurrence of.. 
Geologic map, of Martinsburg, 
trict 
of Placerville, Cal., district 
of western Vermont slate di 
11 
Va., dis- 
120 
56 
ict 88,100 
use of 44-45 
Geology of slates 34 
Georgia, slate of, analyses <>f 60 
slate of, geology of 59 
production of 126-131 
. uses of 60 
Germany, slates of, analyses of 34-35 
Glossary of terms used 146-147 
Gorham, Vt., cleavage hands in, figure 
showing 32 
Gosselet, J., diagram by 23 
on folding 22 
i >n slaty cleavage 22-23 
figure explaining 23 
Grain, character of 25,27,45-46 
Granite, slate in proximity to 34 
Granville, N. V., slate deposits at... 17,29,93,124 
Graphite in slate, occurrence of 11 
i ; raptolites, occurrence of 95, 99 
Guilford, Vt., slate deposits at 89 
Gulf Slate Co., slate deposits of 52 
Gypsum in slate, occurrence of 11,76 
II 
Hampton, N. V., slate deposits at 93, 124 
Hampton-Janesville, Vt., section through.. 95 
Hardness of slate, tests for 48 
Harker, A., on cleava r ;e 24 
Harris, Abraham, slate prospect of 70 
Hathenbuck, E. W. C, slate deposits of 89 
Hayes, C. W.,on Georgia slates 59 
Heimbach, Pa., slate quarry at 78, 121 
Hematite in slates, occurrence of 11,12,14 
Hill, Lawrence, slate prospects of 67 
Hillebrand, W. F., analyses of slates by 15-17, 
36-38, 73-74, 84, 105-108, 110 
on chemical composition of roofing 
slates 39-42 
Hincum Pond, Vt., plicated joints in slate 
at 2S-29 
Hitchcock, C. IE, on Maine slates 60 
Hogbacks, description of 29-30 
See also shear zones. 
Hoosick, X. V., slate quarry at 74 
Hornblende in slate, occurrence of 11 
Hoi Springs, Ark., slate deposits near 52 
Hudson grit, slate beds in 71,75,95,93 
Hughes, William, quarry of (Slatington, 
Pa.), structure in, figure show- 
ing 83 
Hutchins,W. M.,on slates 13,49 
