508 



INDEX. 



Page. 



Sedimentaries, contact with, granite, described 194-198 



plate of 300 



included in dolerite 203 



included in granite 195 



of Hemlock formation described 152, 153 



of Upper Huronian described 165-174 



volcanic, described 136-145 



plate of 296 



Sericite from feldspar 52, 89, 99, 101, 111, 127, 131, 477 



included in quartz 51 



of acid lavas 91 



of metabasalt 99, 101, 127 



of Eandville quartzite 52 



of rock intermediate between quartzite and 



granite 51 



orientation of 51, 478 



Sericite-scbiat from conglomerate 475 



from graywacke 57 



of Hemlock formation 443 



Serpentine from bronzite 238 



plate of. 306 



from bronzite-norite-porphyry 246 



from olivine 213,217,251,255 



included in pyroxene 245 



intergrown with augite 253 



of picrite-porphy ry 213, 214, 218 



pseudomorphs 214 



pseudomorpbs after olivine 253 



pseudomorphs after pyroxene 218 



Sheldon &. Schafer mine. (See Columbia mine.) 



Sholdeis exploration 447, 449 



Siamo slate 451 



correlation of xxv, xxvi 



Siderite altering to hematite 168 



altering to limonite 168 



altering to magnetite 168 



including iron oxide 133 



interbanded with clay slate 168 



of graywacke 170 



of Groveland formation xx,420 



of metabasalt 117, 133 



of siderite slate 62 



origin of 168 



replaced by silica 134 



replacing calcite 133 



source of iron ore 70, 71, 184 



Siderite -si ate of Mansfield formation described 62 



of Upper Huronian 168 



relations to clay slate 63 



Sideritization of metabasalt 117 



Sidnaw (town) 175 



Silicification of metabasalt 130, 133, 134 



of siderite 134 



Silurian rocks, unconformity with underlying rocks . 26, 376 



Slates described 14, 153, 169-174, 481, 482 



alteration of 14, 166 



of Mansfield formation described 204-211 



altering to chlorite-schist 166 



altering to mica-gneiss 166 



argillaceous 14 



fragments in Hemlock XuSb 76 



from Benson, Vt., analysis of 61 



from Hampton village. N. T., analysis of 61 



from Janes ville, K. T., analysis of 61 



from South Poultney, Vt., analysis of 61 



hornblende, described 13, 14 



Page. 



Slates of Hemlock formation 153 



of Mansfield formation, described 57-62 



of Sturgeon Hi ver dolomite formation, described. 481,482 



of Upper Huronian 166 



described 169-174 



relations to ore deposits 68, 182 



transfer of material from basic intrusives 2U 



{See Mansfield formation.) 



Smyth, H. L.,on peneplain 31 



on Kand ville dolomite 27, 53 



referred to xv. xvi, 22.26, 50,74, 152 



Smith, G. 0., on Archean granite 38 



on ellipsoidal structure 118,119 



Smith mine. {Sec Armenia mine.) 



Soapatone associated with ore deposits 68, 183 



of Mansfield formation 57 



Soil of Crystal Falls district 36.37 



Solar compass, use of 24 



Sorby, H. C, on enlargement of quartz grains 404 



South iron range. {See Menominee range.) 

 South Mastodon mine. {See Manhattan mine.) 



South Mountain, Pa 124 



South Poultney, Vt., analysis of slate from 161 



Sphene from biotite 192.225 



from ilmenite 239 



from titanic iron 144,146,170,193,212,239 



included in biotite 225 



incl uded in epidote-zoisite 225 



including apatite 244 



of acid lavas 91 



of basic dikes 47 



of biotite-granite 192, 193 



of gabbro 239 



of graywacke 170 



of metabasalt 100 



of metadolerite 202 



of tuff 141 



of volcanic conglomerate 144 



pseudomorphs after magnetite 46G 



surrounding magnetite 466 



Spherulitic texture in metabasalt {see Yariolite.) . 98, 102, 108 



Spilite 98 



Spilosite of Mansfield formation 64 



described 206. 207 



plateof 302,304 



analyses of 207 



analysis of compared with analyses of clay slate 



and adinole 210 



gradation to desmosite, plate of 306 



included in dolerite 204 



Spinel included in hornblende 236 



included in olivine 251,252,255 



intergrown with hornblende 256 



of gabbro and norite 236 



of peridotite 252 



Spurr, J. E., on oval areas in iron formation 422 



Squaw Lake 335 



Stalactitic ore 18.0 



Staurolite altering to muscovite 196 



of graywacke 167 



of mica-schist 195 



Steiger, George, analyses by 59, 



61, 203, 208, 210, 242, 244, 245, 263, 264 



Stokes, H. N., analyses by 103, 



106, 207, 210, 219, 231, 259, 263, 264, 389, 391,-394, 397 

 referred to : . 260 



