s, phosphates, 104-106
potash, 112
_See also_ North Africa.

Tunnels, application of geology to construction, 414-415

Turkey, borax, 275
chromite, 178-179
emery, 268, 270

Turquoise, 290, 293

Tuscany, Italy, borax deposits, 275

Umpleby, Joseph B., 383

Underground waters. See Ground-waters.

United Kingdom. See Great Britain.

United States, abrasives, natural, 267-270, 397, 398
aluminum, 242-245, 397
antimony, 247-248, 249, 398
arsenic, 250-251, 397
asbestos, 270-272, 398
asphalt and bitumen, 152, 397
barite, 273-274, 397
bauxite, 242-245, 397
bismuth, 252-253, 397
borax, 275, 276, 397
bromine, 277, 278, 397
cadmium, 253-254, 397
cement, 87-88, 397
chalk, 83, 398
chromite, 179, 398
coal, 115-118, 126, 127, 366-367, 397
common rocks, 82-88, 397
copper, 197-208, 396
corundum, 267-268, 270, 398
diatomaceous earth, 269, 398
emery, 267-268, 270, 397
feldspar, 86, 397
ferro-alloy minerals, general, 154-158
fertilizers, general, 100-101
fluorspar, 194, 397
fuller's earth, 278-279, 397
garnet, 268, 260, 398
gold, 222-230, 397
graphite, 279-283, 398
grinding pebbles, 268, 398
gypsum, 283-284, 397
iron, 158-163, 166-171, 397
lead, 209-213, 397
lime, 82-83, 397
magnesite, 191-193, 397
manganese, 174-177, 398
mercury, 256-259, 398
mica, 286-287, 398
mineral paints, 397
molybdenum ores, 186-187, 397
monazite, 288, 289, 398
natural abrasives, 267-270, 397, 398
natural gas, 151
nickel, 181, 398
nitrates, 102, 398
oil shales, 150-151
petroleum, 128-150, 396, 398
phosphates, 104-107, 397
platinum, 238-240, 398
potash, 112-114, 398
precious stones, 290, 292-293, 398
pumice, 268, 398
pyrite, 107-109, 397
salt, 294-298, 397
silica, 195-196
silver, 231-237, 397
stone, 82-88, 397
sulphur, 109-111, 397
talc, 299, 300, 397
tin, 261, 262, 398
titanium, 190-191, 398
tripoli, 269, 398
tungsten, 183-185, 398
uranium and radium, 264-266, 397
vanadium, 18, 188, 398
zinc, 214-220, 398
zirconium, 189, 398

United States, control of various minerals in other countries, 64, 102,
129, 152, 163-164, 165, 175, 180-181, 184, 187, 189, 191, 198,
222, 232, 238, 243, 261
laws relating to o