504 



INDEX. 



Page. 



Muscovite of sedimentaries metamorpliosed by intru- 



eion 195,197 



of spilosite, i^late of 30-i 



parallel growth with biotite 170 



relations of orientation to biotite 484 



Muacovite-biotite-gneias, plate of 29S 



of Sturgeon foni" ation 401 



MuscoTite-biotite-granite 190 



described 193, 19i 



Navitic texture in metabasalt 9S, 99, 104 



Needle, dip, use of 344 



described 342-343 



Needle, horizontal, deflection of, figure of 345 



Negative crystals in quartz 41 



Negaunee iron-bearing formation 451 



correlation of xs, xxv, xxvi, 449, 455 



distribution of 453-455 



magnetic observations in 338, 339 



relations to Groveland formation xx, 449, 455 



Net River described 31 



New Haven 96 



Norite, analyses of 244, 245, 263-264 



described 233-249 



North iron range. (See Felch Mountain range.) 



Northeastern area described 451-457 



Northwestern mine 399, 407 



Norway Portage 167,173,174,191,226 



Norway Rapids ~ 240 



Norway slates, correlation with Mansfield schist. . . . 413 



O. 



Octahedrite, included in hornblende 236 



of gabbro and norite 236 



(See Anatase.) 



Oligoclase in biotite-granite 41,42 



Olivine, altering to magnetite 217 



altering to pilite 211,217 



altering to serpentina. 213,217,251,253,255 



altering to tremolite 218 



crystallization of 257 



included in hornblende 251, 257, 260 



included in pyroxene 255, 256 



including spinel 252, 255 



of amphibole-peridotite 255 



of gabbro and norite 238,239 



of metabasalt 104,211 



of metadolerite 201 



of peridotite 251 



of picrite-porphyry 213, 217 



pseudomorphs of 203, 213, 214 



zonal intergrowtb. with augite and hornblende. . 255-260 



plate of ' 320,322 



zonal structure in 258, 259 



Olivine gabbro, gradation to amphibole-peridotite .. 254-260 



Oolitic texture in dolomite 435, 437 



Ophitic texture in diorite - . . 223 



in gabbro 233 



in greenstone 483 



in hornblende-gabbro 240, 244 



in metabasalt 212 



in metadolerite 48, 200 



in tonalite 230 



Organic matter, origio of cherty carbonate 184 



Orientation of actinolite 



of amphibole 127, 



of biotite 393, 425, 



of calcite 



of chlorite 118,127, 



of dolomite 



of feldsijar 84, 90, 171, 



of hematite 



of hornblende 174, 214, 215, 395, 



of mica 43,44,51,89,91,198,387- 



of phenocrysts of granite-porphyry , 



of quartz 51,84,118,132,133,171,402, 



Ornamental stones of Hemlock formation described. 



Orthoclase, alteration of 



of acid lavas 



of biotite-granite 



of diorite 



of granite 



of muscovite-biotlte-grauite 



of rhyolite-porpbyry 



Ottrelite of chlorite-schist 



of Hemlock schist 



Oval structure in G-roveland formation described... 



P. 



Pahoehoe structure in basalt (see Ellipsoidal struc- 

 ture) 119,120,121, 



Paint River 11, 21, 161, 164, 167, 174, 179, 187, 



described 



Paint River district 



iron ore of 



named by Brooks 



Paint Paver Falls 



Paint River Iron Company. (See Paint River mine.) 

 Paint River mine 



dike in 



location of 178, 



ore dejjosits of 



table of shipments from 



Paint rock associated with ore deposits 



of Mansfield ore deposit 



Palagonite tuffs, use of term 



Paleozoic rocks, deposition of 



relations to lower formations 26, 28, 



(See Potsdam sandstone.) 



Paragonite from feldspar 



Parallel texture of hornblende-gabbro 



plate of 



Patton, H. S., on hornblende 



on hornblende-picrite 



referred to 



Peevie Palls 



Pegmatite in Randville formation 



intruding mica-schist 



veins in greenstone 



Pegmatitic texture in gneisses 



Peneplain of Crystal Falls district, relations to 



Michigan and "Wisconsin peneplain 



Penokee district, correlation of series 



iron formation of, located by magnetic work 



ferruginous carbonates of 



Peridotite described 



age of 



analyses of 



crystallization of minerals 



distribution of 



Page. 



105 

 214, 486 



396, 465 

 388, 478 



404, 475 

 153, 154 



123, 124 

 190, 194 



183 



183 

 , op. 186 



183 

 op. 136 



183 

 57,68 



138 



xxrv 



376, 383 



33,31 



XXI, 189 



24 



130 

 249-262 



262 

 263, 264 



262 

 249, 250 



