IN'DEX. 



Acid rocks. (See Rhyolite.) 



Ages of eruptions 39,50,59,61 



AUuvial cones 39,214,249,277 



Alluvial conglomerates, general discussion of 214 



Alumina in volcanic rooks 89,117,123 



Andesite, augitic: 



Classification of 101,108,109 



Occurring in the — 



Aquarius Plateau 293,295 



Awapa Plateau 275 



Fish Lake Plateau 261.266 



Mount Hilgard 272 



Markiigunt Plateau 196,204 



Monroe Amphitheater 229,239 



Sevier Plateau 229,232,235,242 



Tushar 177,181 



Order of sequence 63,65,67,131-137 



Andesite, hornblendic: 



Classification of 110 



Occurrences 230,237,242,260 



Order of sequence 67,131-137 



Andesite, quartz. (iSee Dacite.) 



Aquarius Plateau, general discussion of (Chap. XII) 284 



Eelatious to District of the High Plate.aus 5 



Argilloid trachyte. (See Trachyte.) 



Archaean rocks 143 



Awapa Plate.iu, general discussion of 272 



Relations to District of the High Plateaus 4 



B.aldy, Mount 172 



Basalt: 



Chemical constitution of 123 



Classificition of 101,110 



Leucite Ill 



Liquidity of , 135 



Nepheliu Ill 



Order of sequence 67,131-137 



Superfusion of 135 



Synthetic character of 122 



299 



