INDEX 





Abyssal eruptive rocks, 184 

 Accessory minerals of igneous rocks, 



37, 39 



Accumulation mountains, 394 



Acid igneous rocks, 40 ; mutual rela- 

 tions of, 45 



Acid secretions in granite, 43 



Actinolite, 16 ; -rock, 78 ; -schist, 78, 

 89 



Adularia, II 



/Eolian basins, 421 ; rocks, 56 ; soils, 



391 

 African lakes, 419 



After-action. See Pneumatolytic action 

 Agate, 5 



Agglomerate, volcanic, 53, 197 

 Alabaster, 30, 66 

 Alaska, indented coast of, 423 

 Albite, 12, 13 



Alderley Edge, ores at, 261 

 Alkali-felspar rocks, 41 

 Allotriomorphic (anhedral) minerals, 



36 

 Alluvial basins, 420 ; clay, 61 ; soils, 



349 

 Almandine, 24 

 Alpine type of folds, 398 

 Alps, 143, 397, 401 

 Alteration of rocks, 37, 212 

 Alteration-pseudomorphs, 38 

 Alum shale, 63 ; slate, 76 

 Amazon, plains of the, 411 

 Amber, 101 

 Amethystine quartz, 6 

 Amianthus, 17 

 Amphibole group, 16 

 431 



Amphibolites, 78 ; soils from, 382 



Amygdules, 125 



Analcite, 26 



Andalusite, 25, 216 ; -slate, 77 ; -horn- 

 fels, 79 



Andes, 143 



Andesine, 12, 13 



Andesite, 48, 86, 87, 89 ; -tuff, '54 



Anhedral (allotriomorphic) minerals, 36 



Anhydrite, 29 



Animal- tracks, 118 



Animals, geological action of, 371 



Anorthite, 12, 13 



Anorthoclase, 1 1 



Anthracite, 71 ; -slate, 76 



Anticlinal double- fold, 139 



Anticlines, 136, 392 



Anticlinorium, 140 



Antrim, plateau-basalts of, 21 1 



Apatite, 30 ; veins of, 218, 265 



Aphanite, 86 



Aplite, 42 



Appalachian Mountains, 399 



Aqueous rocks, 55 



Aragonite, 29 



Aralo-Caspian depression, 412, 419 



Archaean rocks, 227, 305 



Arctic pl:int- and animal-remains in 

 Pleistocene, 98, 318 



Arenaceous rocks, soils from, 383 



Arenaceous shale, 82 



Argillaceous rocks, 76, 82, 93 ; con- 

 cretionary, 124; soils from, 384 



Arkose, 61, 373 



Artesian Wells, 360 



Asbestos, 17 



