INDEX. 



501 



M. 



Page. 



Magnetic instruments, use of, described 341-344 



Magnetic observations 24, 77 



described 336-372 



effect of intrusives on, described 371-372 



in Groveland formation 377,415,416,447,448 



in Negaunee formation 453, 455 



in metabasalt 134 



in Sturgeon River tongue 460 



in Upper Huron i an 175,176 



described 156-157 



enfolding 366-373 



Magnetic rocks described 338-341 



depth of, determination of 354-356 



Magnetism in magnetic rocks, distribution of 339-341 



Magnetite altering tosphene 466 



from basic volcanics 152 



from hornblende 215 



from olivine 217 



from siderite 168 



included in microcline 394 



included in biotite 252 



included in dolomite 436 



included in hornblende 487 



included in quar(z 394 



of ampbibole-schist 466 



of Bone Lake schist 151 



of graywacUe' 170, 176 



of greenstone 470, 487 



of iron-bearing formation 338, 417, 419, 421 



of metabasalt - 100 



of metadolente 202 



of peridotite 261 



of picrite-porpby ry 218 



of pyroclastics 147 



of sedimentary inclusions in granite 197 



of volcanic conglomerate 143 



surrounded by leucoxene 466, 470 



surrounding amygdaloidal cavities 102 



titaniferoua 47 



Malacolite included in hornblende 238 



of gabbro and norite 238 



Manhattan mine, location of op. 186 



table of shipments from op. 186 



Manganese ore of Upper Huronian 181,182 



Mansfield (town) 12,54,130,178,203,204 



Mansfield formation described XX, 54-73, 411-415, 437-440 



adinole of, described 208-209 



Bessemer ore in , 27 



clay slate, described 57-62 



analysis of 59, 61 



compared with analyses of contact product. 209-211 



compared with clay 60 



compared with New York slate 61 



compared with Vermont slate 61 



chert of described , 62 



correlation of xxv, xxvi, 413 



desmositeof 207 



distribution of 27,54,438 



exploration in 73 



folding of 438,439 



gray wacke of, described 56-57 



iron ores of 27, 62 



described 65-73 



metamorphosed by intrusives 204-211, 413 



of Felch Mountain range described 411-415 



Page. 

 Mansfield formation of Michigamme Mountain and 



Fence Kiver areas described 437-440 



phyllite of, described 57-62 



possible continuation of 55 - 



relations to adjacent formations 63, 64 



relations to Archean 424 



relations to Groveland formation 411, 413, 438, 447 



relations to Hemlock formation xx, xxi, xxvi, 64, 76 



relations to intrusives 63, 64, 203, 204 



relations to Eandville formation xx, 55, 411,434, 438 



relations to slate of Michigamme Mountain 56 



relations to Upper Huronian xxn 



siderite-slate of, described 62 



spilosites of, described 206-207 



structure of 64 



thickness of xvii, 64, 65, 412, 438, 439 



topography of 54, 438 



Mansfield mine 27 54 411 



described 65-70 



analyses of ore from 69 



cross section of G3 



concentration of ore at ,.. 72 



figure of cracks in 65 



location of op. 186 



table of shipments from op. 186 



Mansfield ore deposit, exploration of 67 



concentration of 72 



origin of 70 



relations to surrounding beds 68 



Marble of Eandville formation 434, 435 



described 408-311 



of Sturgeon Eiver dolomite 480, 481 



relations to iron-ore formation 376 



relations to quartzite 376 



(See Dolomite, Eaudville dolomite.) 



Marquette district, correlation of formations of xxv, 



XXVI, 189, 330, 451-457, 470-471 



folding of 26, 452 



Clarksburg formation of 132 



iron-bearing formation of, connection with Crys- 

 tal Falls iron-bearing formation.. 330 



Martin -Garcia, oli vine-gabbro from 255 



Martite of Groveland formation 417^19 



Mary Lake lei 



Mastodon Iron Co. (See Mastodon mine.) 



Mastodon mine, analysis of ore from 181 



caving system at 185 



location of 179, op. 186 



method of mining at 184, 185 



table of ahiptnents from op. 186 



Matrix of ellipsoidal metabasalt 122, 132, 133, 135 



described 114-118 



plateof 116,284,298 



Matthews, E. B., indebtedness to 331 



referred to 22 



Maurer, E. E., referred to 22 



McCutcbeon's Lake 91 



McKim, J. A., referred to 22 



McNair, F. W., referred to 22 



Melaphyres 98 



Menominee district, correlation of formations of xxv, 



XXVI, 330 



folding of 26 



relations to Crystal Falls district 11, 25 



structure of 378 



iron ore of, compared with Crystal Falls iron 

 ore 19,181,186 



