I N D E X . 
A. 
Page. 
Albion quarry, Pen Argyl, Pa 78-80 
Analyses of slates, chemical... 16-18,34-38,41-42, 
53, 57-58, 60, 71, 73-74, 88-89, 10-5-108, 111 
Analyses of slates, microscopic or mineral . 12, 
14-16, 51, 53-55, 57, 63-67, 124 
Analysis, microscopic, method of 48-49 
Anatase in slate, occurrence of 11, 114 
Andalusite in slate, occurrence of 11,14,87 
Apatite in slate, occurrence of 11 
Aqueous sediments, slates derived from 5-6 
Ardennes, France, slates of, character of. . . 6 
slates of, cleavage in 27 
minerals in 12 
waste in 42 
Arizona, slate of, description of 51 
Arkansas, slate deposits of, description of.. 52-53 
slate deposits of, location of 51-52 
location of, map showing 52, 54 
slate of, analysis of 53 
character and mineral composition 
of 53-55, 124 
mineral particles in 13-1 4 
production of 126-131 
Arvonia, Va., slate deposits at 19,31, 
33,113-115,124-125 
Auld & Conger, slate quarries of 77,98 
Ausweichunj: s clivage. See Slip cleavage. 
13. 
Bailey, E. H. S., on slate characteristics... 81,124 
Bangor, Pa., slate quarries at 75-77, 125 
Barite in slate, occurrence of 109 
Bate. See Slip cleavage. 
Baur, , on cleavage 24 
Becker, G. F., on cleavage 10 
on cleavage bands 32 
Bedding, character of 13-22 
erosion of 9 
origin of 18 
relations of cleavage and 22-23, 42-43 
figures showing 23, 43 
views of 18 
Bennett Creek Slate Co., slate quarry of... 69-70 
Benson, Vt., slate deposits at 110 
slate from, analyses of Ill 
features of 33, 1 10, 124 
Bibliography of slate 138-145 
Biotite in slate, occurrence of 11,14 
Blissville, Vt., section at .' 97-98 
section at, plate showing 20 
Blue Mountain quarry, Pa., view of 82 
Page. 
Bottinger, C, on frost action as related to po- 
rosity in slates 48 
Brandon Slate Co., slate deposits of 104 
Bremo, Va., slate deposits at 11,115, 124 
Brennan & McElwen, slate deposits of 53 
B rogger, on shear zones 29 
Brownville, Me., quarries at 65-67, 124 
quarry at, plate showing 66 
slate from, thin section of, plate show- 
ing 64 
Buckley, E. R., on Arkansas slates 52 
C. 
Calcite in slates, occurrence of 11, 76, 109 
California, geologic map of part of 56 
igneous slate in, analyses of 58 
roofing slate in, production of 59 
slate deposits of 56-59 
slate of, analyses of 57-58 
characteristics of 57-58, 124 
market for 59 
production of 126-131 
structure of 56-57 
transportation of 59 
Cambrian time, crustal movements in 34 
slate deposits of 70, 93-110 
bedding in, plate showing 20 
shear zones in, plate showing 30 
Campbell and Donald, on slate character- 
istics 47 
Carbon, color of slates due to 7 
Carbonaceous matter in slate, occurrence of. 11 
Carbonate in slate, occurrence of 14 
Castleton, Vt., slate deposits at 21 
Cedar Point, Vt., slate deposits at 15-16,21 
Chapman, Pa., slate deposits at 80-81, 125 
Chapman Slate Co., slate quarries of. . 80, 122, 124 
Chemical analyses. See Analyses. 
Chemistry of slates, account of 34-42 
Chili Bar Slate Co., slate quarry of 58 
Chlorite in slates, occurrence of 11, 12, 14, :0J 
Classification of slates 5-6 
Clay in slates, occurrence of 46 
Clay slates, origin of 5,8 
See also Slates. 
Cleavage, cause of 7-8 
character of 5. 8-9, 18-19, 22-25 
curvature of 24 
relation of axes of folds to 23 
relation of bedding planes to 22-23,42-43 
figures showing 23,43 
surface of, character of 46 
149 
