490 



INDEX. 



Page. 



Araphibolite of ArclieaD, described 395-397 



from basic Tolcanics 152 



intrndiog mica-schist 392 



Amygdnloidal texture in metabasalt. . . . 102, 113, 122, 123, 442 



described 124-126 



plate of 280,282,284,290 



cause of distribution of, in basic lavas 95 



in eruptive breccia 136 



in Hemlock schist 445 



in pyroclastics 138, 146 



Amygdules of calcite, plate of 282 



of chlorite, plate of 284 



of feldspar, plate of 284 



of quartz, plate of 284 



order of deposition of 125 



pressure effects in 126,128 



Analyses of adinoles 208 



of araphibolite 397 



of clay slate 59, 61 



of clay slate, spilosite, andadinole, comparison of 210 



of dolomite 409, 435 



of gneiss .^. 391 



of granite 389 



of hornblende 242 



of hornblende-gabbro 263-264 



of iron ore, by Brooks, referred to 19 



of iron ore 181 



of Mansfield mine 69 



of Mansfield slate 59, 61 



comparison with contact xiroducts 209-211 



of metabasalt 103, 106, 107 



of mica-diorite 231, 263-264 



of raica-sebist 394 



of norite 245,263,264 



of peridotite 259. 263, 264 



of picrite-porphyry 219 



of spilosite 207 



Anatase included in hornblende 236 



of gabbro and norite 236 



of metabasalt 129 



(See Octahedrite.) 



Andesine, alteration of 224 



altering tomuscovite 224 



altering to epidote-zoisite 224 



of diorite 224 



of gabbro and norite 233 



of metabasalt 104 



twinning of 104 



Andesite, of Hemlock formation 107 



Anticline determined by magnetic observations. 366, 372, 373 

 described 370-371 



Antoine dolomite of Menominee district corre- 

 lated XXV, XXVI 



Apatite incliided in biotite 217, 234, 239 



in feldspar 234 



in quartz 194, 419, 420 



in sphene 244 



of acid lavas 91 



of biotite-granite 192 



of gabbro and norite 239 



of metabasalt 99 



of periodite 252 



of picrite-porphyry 216 



of outlining feldsps?!- crystals 239 



Aphanitic texture in metabasalt 98, 99, 212 



Apobasalt, use of term 96, 98 



Aporbyolite with perlitic parting, plate of 274 



Aporhyolite-porphyry described 87 



breccia, plate of 276 



perlitic parting of, plate of 276 



pressure effects in, plate of 276 



use of term 80 



Aragon mine 69 



Archean, described xvili, 38-49, 385-397, 428-430, 463-471 



acid dikes in, described 45-49 



age of 39 



basic dikes in, described 46-49 



biotite -granite of, described 40-43 



dikes in, described 45-49 



distribution of 38, 39, 331, 427 



ellipse 26, 38. 333, 427 



erosion of xxiv, 39 



folding of XXIII 



intrusives in xvtu, 38, 45-49 



metamorphism of xviii, xxiii 



of Crystal Falls district correlated with Archean 



of Marquette district xxv, xxvi 



of Felch Mountain range, described 385-397 



distribution of 385 



topography of 386, 387 



of Marquette district correlated with Archean 



of Menominee district xxv, xxvi 



correlated with Archean of Sturgeon Hirer 



tongue 470-471 



distribution of 452-453 



of Michigamme Mountain and Fence Kiver areas, 



described 428-430 



of Sturgeon River tongue, described 463-471 



comparison with Archean of Marquette dis- 

 trict 470-471 



relations to Algonkian 459, 460, 461-463 



origin of 39 



relations to Algonkian xvii, 



331, 378, 379, 386, 399, 427, 458, 460, 461-463 



relations to Cambrian 26, 331 



relations to drainage 334, 335 



relations to Groveland formation 416, 424 



relations to Huronian. {.See Relations to Algon- 

 kian.) 



relations to Lower Huronian xix, 55 



relations to Mansfield formation 434 



relations to overlying formations 39 



relations to Paleozoic rocks 26, 331 



relations to quartz-porphyry 429 



relations to Randville dolomite xix, 51,53, 55,407 



relations to Silurian rocks 26 



relations to Sturgeon quartzite xix, 398, 401 



relations to Upi>er Huronian xxn 



topography of 38,39,333 



Arenaceous slate group of Rominger 164 



Argentine Republic, gabbros of 255, 256 



Arkose of Sturgeon River conglomerate formation 



described 478-479 



pressure effects in 479 



Armenia mine, description of ore body at 183 



location of, 178 ; op 186 



table of shipments from, op 186 



Ash, beds described 142-1 43 



Azoic system 16, 17, 375 



of Sturgeon River tongue 460 



Augite altering to hornblende 100 



altering topilite 211 



