INDEX. 



601 



Plagioclaae, of greenstoue-schist 206 



of Kitcbi schist 163, 164 



of mica-gneiss 459 



of mica-schist 443 



of Mona schist 155, 157, 158 



of muscovite-granite 175 



of porphyrite 521 



of quartz-diabase 519 



of recomposed ore 438 



{See Feldspar.) 



Piatt mine 212, 213, 215, 298, 299, 311, 383 



Plain of denudation. (See Denudation, plain of.) 



Pleistocene 257, 332, 557 



Point Ko. 2 west of Presque Isle 23 



Poroditein Kepublic andHolyoke formations 139 



Porter, referred to 94 



Porphyry 159, 200 



Porphyry Tein in granite 10 



Porphyry- tuff 159 



Porphyrite 139,164,520-521,525 



PorphjTitic diabase 521 



Porphyritic granite 209 



Porphyritic greenstone 505. 508-509 



Porphyritic syenite 15 



Post- Clarksburg greenstones 524 



described 518-522 



Potsdam sandstone 26, 27, 56, 71, 76, 115. 134, 184, 241 



unconformity -with Azoic 120 



unconformity "with underlying series 112-113 



{See Cambrian sandstone, Lake Superior sand- 

 stone, Old red sandstone, Sandstone.) 



Pre- Algonkian 149 



Pre-Cambrian formations 129. 143 



classification of 112-113 



unconformity between 137 



Pre-Clarksburg greenstones 522-523 



described 488-518 



Presque Isle 9, 13, 



15, 16, 22, 23, 25, 28, 35, 60, 67, 76-77, 

 93, 99-100, 103, 128, 139, 183-184 



Pressure effects in biotite-granite 172, 173-174 



in conglomerate 270, 264, 289, 301, 428, 431, 442, 443 



in feldspar 413 



in ferruginous chert 370 



in gneiss 527 



in gueissoid granite 172, 173-174, 210, 211 



in granite 277, 278 



in gray wacke 229, 230, 233, 242, 267, 268, 319, 448 



in iron ore 431, 432, 433 



in lahpeming formation 441 



in jaspilito 376. 427 



in Kitcbi schist 165, 166-167, 169 



in Kona dolomite 247-248, 251 



in Mesnard formation 223, 224 



in mica-achist 449 



in mica-slate 449 



in muscovite-granite 175 



in Xegaunee formation.... 330 



in novaculito 267 



in ore and jasper conglomerate 426 



in Palmer gneiss 214-215 



in quartz 226, 227, 



228, 265, 268, 275, 289, 290, 291, 308. 318, 368, 

 373, 382, 413, 414, 415, 422, 429, 439. 453, 458 



in quartzite 226, 



228, 229, 242, 288, 289, 290, 293, 300, 301, 

 303. 309, 310, 313, 412, 433, 434, 435. 438 



Pressure effects in recomposed jasper 



in slat e 233, 242, 260. 261, 266. 267, 



(i'ci? Cleavage, Dynamic metamorphism, Fiasilitj*. 

 Mashing, Schistosity.) 



Primary rocks 



Prospecting for iron ore 



Protorozoic 



Pseudo-conglomerate 223, 243, 260, 269, 274, 288, 



Pseudo-pebbles in conglomerate 



Pseudo-unconformity between cherty quartzite and 



truncated layer of dolomite, figure of 



Pseudomorphs of calcite alter plagioclaae 



of chlorite after amphibole 



of chlorite after garnet 



of t-hlorite after plagioclaso 



of chlorite after olivine 



of hornblende after augite isg 



of leucoxene after ilmenite 



of leucoxene after sphene 



of limonite after olivine 



of quartz after plagioclaso 



Pumpelly, R., on garnet pseudomorphs in chlorite- 

 scbist 



on geology of Marquette district 



on iron ores of the United States 



on structure of iron-bearing aeries 



referred to 1,7,110,404,421,503, 



Putnam, B. T., on composition of iron ores 



referred to 



Pyrite 



of gray wacke 



9, 10, 19 



405-407 



109-110 

 109-110 



ofi 



of slate 



Pyroclastic beds 



rocks 



Pyrolusite 



Pyroxene of diabase dikes. 



of Mona schists 



{See Augite.) 



Q. 



Quaquaversal dip of iron-bearing formation 329,333 



of Marquette series 572 



Quarry at Carp River 295, 303 



Chocolate Flux 55 



Quartz, concretionary arrangement of 399 



fragments in Clarksburg conglomerates 477 



from feldspar 226, 



265, 290, 302, 318-319, 327-328. 381, 422, 

 435, 438. 442, 448, 449, 450, 453, 458, 527 



from aiderite 419,422 



grains, enlargement of {see Enlargement of 



quartz grains), 

 grains, parallel arrangement of {see Parallel ar- 

 rangement of quartz grains). 



in nodules 255 



in veins {see Veins of quartz). 



of acid schists I6O 



of amphibole-schist 207 



of basal conglomerate 536 



of biotite-granite 172, 174 



of biotite-scbist 196. 199 



of brecciated chert 246 



of brecciated slate 263 



of cherty siderate , 340 



of Clarksburg sediments 472 



