INDEX. 



Adobe, 121, 320 



chemical analyses of, 321 



distribution of, 320 



thickness of, 321 

 JEolian deposits, 331 



rocks, 138 

 Agalmatolite, 108 

 Alabaster, 109 



Alaska, rock weathering in, 264, 270 

 Albite as a rock constituent, 16 

 Alkali of soils, nature of, 359 

 Alluvial cones, 50 



deposits, 308 



mechanical analyses, 314 



plains, formation of, 277 



plain of the Mississippi, 312 

 Alnoite, analyses of, 210 



weathering of, 209 

 Alumina of soils, 362, 363 

 Aluminum as a constituent of the 



earth's crust, 5 

 Alum shales, 121 

 Amianthus, 107 

 Ammonia in atmosphere, 154 

 Amphibolite, 148 



Amphibole, analyses of fresh and de- 

 composed, 19 

 Amphiboles as rock constituents, 18 

 Amygdaloid, 85 

 Anacostia river, filling of, 311 

 Analyses, calculation of results, 188 



of fresh and decomposed rocks, 

 discussion of, 191 



of granite, discussion of, 187 

 Anamesite, 87 

 Andosites, the, 79 



chemical composition, 79 



classification of, 80 



colors of, 80 



mineral composition, 79 



nomenclature, 80 



structure, 79 



weathering of, 207 

 Anhydrite, 110 



Animals effective in promoting de- 

 composition, 182 

 Animal life, effect on soils, 328 

 Anorthite as a rock constituent, 16 

 Anthracite coal, 131 



Ants as promoters of decomposition, 



effect on soils, 379 

 Apatite, 111 



as a rock constituent, 25 

 Aplit defined, 63 

 Apo-rhyolite defined, 68 

 Aqueous rocks, 99 

 Aragonite as a rock constituent, 24 

 Arenaceous rocks, 113 

 Argillaceous rocks, 117 

 Argillite, analyses of, 214 



composition of, 119 



weathering of, 213 

 Arkansas river, sediment in, 277 

 Atmosphere, action of, 154 



composition of, 154 

 Augite altered to hornblende, 36 



porphyries, see melaphyr, 85 



vitrophyrite, 86 

 Augitite, 95 



chemical composition of, 96 



Bacteria, action of, 181 



effect of, 385 

 Barite, 110 

 Barium as a constituent of the 



earth's crust, 7 

 Basalt, analyses of, 205, 206 



Bohemia, weathering of, 205 



^France, weathering of, 206 

 Basalts, the, 86 



chemical composition, 86 



classification, 86 



colors, 86 



mineral composition, 86 



nomenclature, 86 



structure, 86 

 Basanite, see Tephrite, 88 

 Bastite, 21 



Bat guano, analysis of, 361 

 Beach sands, 329 

 Beauxite, 102 

 Bermuda, sand of, 329 



limestone, weathering of, 233 

 Biotite as a rock constituent, 22 

 Bituminous coal, 130 

 Black earth of Russia, 316 

 Bog deposits, classification of, 306 



391 



