467 



Rock, definition of 5 



Rock-forming agencies 8 



Rocks, classification of 9 



ROGEKS, decomposition of felspar. . 413 



ROHRBACH, teschenite 95,359 



ROSE, G., granitite 291 



serpentine after olivine 104 



ROSENBUSCH, basalt 136 



contact-rnetamorph- 



ism 373 



diabase 184 



gabbro 132 



granite rocks 15 



granular and porphy- 



ritic textures ... 52 



lamprophyre 351 



leucophyre 225 



limburgite 173 



mica-traps 351 



micro-felsite 402 



-rutile 219 



spherulites 33 



theralite 359 



Ross, rocks of St. Kilda 247 



ROTH, J., origin of serpentine ... 105 



Rutile after iron- ore 230 



in actinolitic schist 243 



in granite 324 



in hematite 167 



in spilosite and adinole .. 219 



RUTLEY, devitrification 810 



felsitic lavas 386 



- fulgurite 18 



rocks of Brent Tor 229 



strain-phenomena in obsi- 



dian 12 



Rhyolite 292 



S 



Sagenite 167 



Salite, conversion of, into serpen- 

 tine 106 



SANDBERGER, F., buchonite ... .. 360 



genesis of serpen- 

 tine 107 



heavy metals in 



rock-forming minerals 37 



- peridotites ... 79 



- proto-lithionite 302 

 Sandstone, alteration of by granite 378 

 Sanidine 296 



in Tardree liparite ... 348 



SAUSSURE, sagenite 167 



Saussurite 148 



Saxonite 80 



Sceyelite... 101 



Schillerization 80 



SCHILLING, labradorite in diabase... 147 



PAGE 



"Schliere" 40 



Schorl-rock 314 



SCHULTZE, serpentine 119 



SCHUSTER, MAX, optical characters 



of felspars 142 



SCROPE, sequence of volcanic rocks 67 



inetamorphism 422 



Segregation veins in metamorphic 



regions 418 



Serpentine 104 



analyses of 124 



from amphibolite Ill 



- from augite 118 



- lattice-structure of ... Ill 



- mesh-structure of ... 109 



- net-structure of 114 



of Anglesea 125 



of Scotland 126 



of the Lizard 120 



schistose 117 



SHARPE, metamorphism 422 



SHEERER, norite 183 



SHENCK, contact-alteration by dia 



base 220 



Sideromelane 137 



Silica-percentage, range of 88 



Silicification of igneous rocks ... 412 



Sillimanite 383 



Skeleton felspars 15 



Slaty greenstone 287 



Snake-stone 217 



Sodalite 364 



Solfataric action, effect of on ig- 

 neous rocks 410 



SOLLAS, specific gravity 47 



SORBY, effect of pressure on solu- 

 bility 394 



Mount Sorrel granite ... 321 



origin of igneous rocks . . . 403 



structure of crystals ... 17 



use of the quartz-wedge . . . 268 



volcanic tuffs 283 



Soret's principle 894 



Specific gravity 48 



Sphene, after iron-ore 230 



of intermediate rocks . . . 262 



Spherulites 15,33,309 



composition of 898 



Spherulitic felsite 334, 340, 347 



Spilosite 218 



Spinellids, in ultra- basic rocks ... 93 



Spotted slate 374 



Staurolite 374,382 



Steatite 116 



STEAD, analyses by 207 



STEENSTRUP, nickel-iron in basalts 88 



STELZNER, melilite-basalt 868 



STERRY HUNT, saussurite 148 



STOCK, analyses by 207 



