INDEX. 
101 
J. Page. 
Jurassic rocks, absence of 17, 64, 65 
K. 
Katz, F. J., work of 12 
Kemp, J. F., on ore deposits 35 
King, Clarence, on faulting 20 
L. 
Laccoliths, analyses of 49, 61 
area and depth of, relation of 47-48, 87-88 
description of 16 
intrusion of 7, 21, 22, 85 
effects of 8, 79, 84-86 
location of 16, 46 
metaruorphism by 8, 79, 84-86 
metamorphisrn of 45 
nature of 7 
petrography of 48-49 
relation of eff usives and 61 
relation of ores to 8, 75-79, 91 
structure of 46-48 
See also Andesite. 
Lake Superior ores, comparison of , with Iron 
Springs ores 73, 95-96 
Lavas, analyses of 58-59, 61 
distribution of 50 
extension of 7, 21, 22-23, 86 
consequences of 9, 75-79, 82, 84-86 
succession of 50 
iron in 81 
metamorphisrn by 43,81-82 
occurrence of 16, 22, 46 
petrography of 50, 57 
relations of laccoliths and 61 
relations of ores and 9, 80-82, 84-85 
Leith, C. K., work of 11-12, 93 
aid of 13 
Lerch, Fred., on Iron Springs ores 13, 71 
Lime, occurrence of 72 
Limestone. See Homestake limestone; 
Claron limestone. 
Limestone-andesite contacts, iron ores at. 7, 67-69 
iron ores at, figures showing 68, 69 
Limestone contact phase, character of... 8,16,67 
consequences of 8 
Limonite, development of 9 
occurrence of . . 7 
Lindgren, W., on ore deposition 35,84,93,94 
Lindsay Hill, sections at, figures showing. . 68, 69 
M. 
McGary claim, map of Pocket. 
Magnesia, occurrence of 72 
Magnetite, alteration of 82-83 
deposition of 7C-77, 79 
occurrence of 7, 70, 91 
vein of, figure showing 71 
Map, of iron-ore deposits Pocket. 
of Iron Springs quadrangle Pocket. 
showing location of district 15 
geologic, of Iron Springs quadran- 
gle Pocket. 
Marshall claim, map of Pocket. 
Metamorphisrn, character of 8, 
10, 25-37, 40, 43, 49, 79, 81-82, 84-86 
Page. 
Metamorphisrn, extent of 16 
See also Homestake limestone. 
Meteoric waters, relation of ores and 95 
See also Weathering. 
Mexico, iron ores in 92 
Milner, Archibald, aid of 13 
Milner, S. C, aid of 13 
Minerals, paragenesis of 85 
Miocene rocks, occurrence of 18 
Missouri, iron ores in 92 
N. 
Nevada, iron ores in 92 
Newberry, J. S., on Iron Springs district. . . 12 
New Mexico, iron ores in 92 
0. 
Ores. See Iron ores. 
P. 
Permian rocks, absence of 17, 65 
Phosphorus, occurrence of 7, 72, 83 
Pinto sandstone, age of 63, 64 
breccia in 39 
character of 38 
conglomerate in 39-40 
contact phase of, view of 74 
distribution of 37-38 
fossils in 40 
limestone in 40 
metamorphisrn of 16, 40 
section of 38 
structural relations of 40-41 
thickness of 41 
Pirsson, L. V., on composition of igneous 
rocks 60 
Pleistocene rocks, occurrence of 18, 44-45 
Pliocene rocks, occurrence of 18 
Pneumatolytic afteraction. See Laccoliths; 
solutions, ore-bearing. 
Powell Survey, on Iron Spring district 12 
Publications on iron ores, list of 97 
Putnam, B. T., on Iron Springs district 13 
Pyroxene-andesite agglomerate and brec- 
cia, description of 55 
Q. 
Quaternary deposits, occurrence and de- 
scription of 44-45 
R. 
Recent deposits, occurrence of 18 
Replacement deposits, iron ores in 7 
Rhyolite, early tuffaceous, analysis of 58 
correlation of 65 
description of 51-52 
Rhyolite, late tuffaceous, description of 56 
S. 
Sediments, correlation of 62-65 
occurrence and description of 
Shrinkage, extent of 20,71,86 
Silica, occurrence of 72 
Sjogren, Hjalmar, on ore deposition 9 1 
Soda, introduction of 8, 77 78,85 
Solutions, ore-bearing, character of. 8, 75-78, 85, 86 
