INDEX. 



1281 



Page. 

 Spencer, J. "W., on depth of decomposition of rocks 



in Georgia 530 



Sperry, F. L., and Penfield, S. L., on aphrosiderite 



at Spuri-mine 303, 305 



Spessartite, chemical and physical constants of . .. 200,399 



occurrence of 301 



Sphalerite, occurrence and genesis of 1151-1152 



Sphere, chemical and physical constants of .. 195 



Spheres, compactly packed, diagram showing, to 

 illustrate continuous openings in 



rocks 133 



Spinel, alterations and alteration products of. 22S, 374, 392 



chemical and physical constants of 200, 228 



occurrence of 228 



sources and modes of formation of 223, 224, 



225, 228, 232, 236, 302, 304, 307, 309, 341, 372, 375, 

 376,379,381,383,388,390,396,400,401,402,408 

 Spring, Walther, experiments of, in compaction of 



clay 100,101 



on production of chemical changes by mechan- 

 ical action. . ._ 48,49 



Springs, carbon dioxide exhaled by 970-971 



carbonates contained in 611 



tufa deposits of. __ 793 



Spurr, J.E., on dolomitization of limestone 800,807 



on gold-quartz veins on Yukon River, Alaska. 1048-1049 



on ore deposits, genetic classification of 1053 



on ore deposits of Aspen mining district, Colo- 

 rado 1084,1204 



on ore deposits of the Mercur mining district, 



Utah i 1208,1213,1215 



on ore deposits of the Monte Cristo district, 



"Washington .. 1033, 1169, 1178, 11S7-1188, 1235 



on ore production from igneous rocks 1043 



on oxidized belt in Monte Cristo district, coinci- 

 dence of, with belt of weathering 1142 



Stability of minerals, dependence of, on chemical 



composition 359 



dependence of, on chemical composition of ad- 

 jacent minerals _ 359 



on chemical composition of circulating solu- 

 tions 359 



on specific gravity 360,361-362 



on symmetry 360-362 



Stable and unstable minerals, examples of 359,360 



Staurolite, absorption of othermineralsinrocksby. 701 



alterations and alteration products of 327-329, 



374,393,403,406 



chemical and physical constants of 200,327 



occurrence of 327 



sources and modes of formation of 327,353,380 



Steamboat Springs, Nev., mineral vein formation 



at 1059,1060,1064,1066 



sulphides in solution at. _ 1106 



Steatite, sources and modes of formation of . . _ 318, 



326, 337, 350-351, 372, 376, 381, 392, 393, 402, 403 

 See also Talc. 

 Stevenson, J. J., on warm or hot springs of Cordil- 



leran regions __ _ 591-592 



Stewart, John, and Gardner, F. D., on calcium chlo- 

 ride deposits near Great Salt Lake . . 542 

 on sodium carbonate in soil at Great Salt Lake. 543 



Stilbite, alterations and alteration products of 334, 



374,393,400 



chemical and physical constants of 200, 330 



occurrence of 331-333 



Stilbite, sources and modes of formation of 262, 



298,372,375,377,397,399 

 See also Desmine. 



Stokes, H. N., on metals, precipitation of 10S2, 



1087, 1092, 1102, 1149 



on precipitation of sulphides 1113,1116-1117 



on production of sodic sulphide from reaction 



of sodic carbonate on iron sulphides. 1107 



onpyriteandmareasite.. _ ___ 1126-1127 



on reaction of zinc carbonate and sodium car- 

 bonate on iron sulphide 1143 



on reversible reaction of ferric and ferrous sul- 

 phates in presence of silver 1100 



on solubility of gold 1090 



Storer, F. H., on chemical action of plants on soils . 454 



on disintegration of rocks by plants 445,454 



Strain in minerals, metasomatism produced by . . 641-042 



potentialization ofenergyby.. __ 690-691 



Strain of rocks, discussion of _ 46-47, 



49-50, 95-98, 597-602, 641-642, 671-675 



Strain and stress, metamorphic effect of _ 46-47 



Statigraphy, igneous rocks as related to 922-924 



metamorphic sedimentary rocks as related to. 917-921 



metamorphism as related to 907-931 



Straw, percentage of potash, soda, lime, etc., in 454 



Streams, concentration of soluble materials by.. 551-554 

 Stream-transported materials deposited inland, dis- 

 cussion of _ __ 559 



Stress, discussion of 597-602 



metamorphic effect of_. _ 46-47 



See also Strain. 



Stretching of rocks, use of term, discussion of 763-764 



Strontium, percentage of, in earth's crust. 936, 1002 



Strontium oxide, percentage of, in earth's crust ... 938 

 Structures of rocks, category of, produced by meta- 

 morphism 37 



coarse, favorable to permanency 40 



emphasis of , by weathering __ 524-526 



obliteration of , by weathering 526-527 



preservation of, after metasomatic alteration. 614 645 



rock flow as affecting 760-762 



variations in 1200-1217 



Struve, F. A. A., on action of carbon dioxide solu- 

 tions on rocks 61,71,476 



Subeapillary openings in rocks, flow of water in. _ 143-146 

 Subsidence and uplift, influence of, on ground- 

 water level 426 



Substitution of bases, alterations produced by 408 



Sudbury, Canada, nickel ores at 1046-1047 



Sulphate of iron, production of 468 



Sulphate of lime. See Calcium sulphate. 

 Sulphate of potash. Sec Potassium sulphate. 



Sulphate order of rocks, features of 788 



Sulphates, alkaline, amount of, annually removed 



from soil 456 



Sulphates, character, occurrence, formation, and 



alterations of._ __ 357-358, 



472, 952, 955, 957, 958-919 



Sulphation, definition of 205 



Sulphidation, alterations produced by 408 



definition of 205 



Sulphidation, deoxidatiou, and car Donation, altera- 

 tions produced by _ 408 



Sivlphide ores, occurrence and genesis of 114S-1153 



Sulphides, cementing action of, in belt of cementa- 

 tion.... 622 



3ION XLVII — 04- 



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