7o6 



INDEX 



Solution of mineral matter, 35 



importance of, 36 



South Africa, glacial Permian in, 474 

 South America, coal in, 457 



Cretaceous in, 545 



Devonian, 413 



Eocene in, 564 



glacial Permian in, 474 



Jurassic in, 507 



Miocene of, 590 



Triassic in, 493 

 South Dakota, Proterozoic rocks' of, 



340 



Spatter-cones, 237 

 Specific gravity of earth, n 

 Spencer, J. W., cited, 605, 646 

 Spergen formation, 427 

 Sphaerexochus mirus, 399 

 Sphenophylls, 458, 461 

 Sphenophyllum longifolium, 461 

 Sphenopteris splendens, 460 

 Spiders, 467 

 Spiral nebula, 303 

 Spiral nebulae, composition of, 304 



evolution of, 305 



organization of, 304 

 Spirifer acuminatus, 416 



arenosus, 415 



biplicatus, 433 



cameratus, 469 



increbescens, 437 



logani, 435 



macropleurus, 414 



marionensis, 433 



murchisoni, 415 



niagarensis, 396 



pennatus, 419 



radiatus, 396 



striatus, 435 



suborbicularis, 435 

 Spiriferina kentuckiensis, 469 



spinosa, 437 

 Spirifers, 418 

 Spisula marylandica, 595 

 Spit, 1 86 

 Sponges, Cambrian, 362 



Ordovician, 385, 386 



Silurian, 399 

 Spouting horns, 181 

 Springs, 48 



Squaloraja polyspondyla, 513 

 Squamata, 551 

 Stalactites, 287 

 Stalagmites, 287 

 Stanton, T. W., cited, 531, 539 



Starfish, Silurian, 396 

 Staurocephalus murchisoni, 399 

 Steatite, 291 

 Stegocephalians, 465 

 Stegosaurs, 517, 518 

 Stenotheca rugosa, 361 

 Sterculia mucronata, 547 

 Stone, G. H., cited, 642, 666 

 Stratification, 269 

 Stratified rock, 9, 269 

 Stratum, 269 

 Stream erosion, 59, 73-80 

 Streams, intermittent, 58 



permanent, 58 



Streptelasma corniculum, 385 

 Streptis grayi, 396 

 Strike, 275 



Strobilops labyrinthica, 644 

 Stromatopora delicatula, 383 

 Stropheodonta concava, 416 



magnifica, 415 



profunda, 396 

 Strophomena subtenta, 382 

 Strophonella punctulifera, 414 

 Structural valleys, 63 

 Subaerial formations, Pliocene, 599 

 Sub-Aftonian ice sheet, 633 

 Subglacial drift, 147, 153 

 Submerged valleys, 171 

 Submergence, causes of, 349 

 Subulites regularis, 381 



ventricocus, 397 

 Succinea avara, 644 



obliqua, 644 

 Suina, 570 



Sun-cracks, 192, 194, 195 

 Sunflower coral, 400 

 Sunstone, 254 

 Superglacial drift, 147, 153 

 Superimposed drainage, 99 

 Surcula biscatenaria, 597 

 Susquehanna River, 105 

 Syenites, 260, 262 

 Synclines, 276 

 Synclinoria, 277 

 Syringopora verticillata, 398 



Tabular joints, 280 

 Taconic Mountains, 371 



age of, 373 



Taff, J. A., cited, 432 

 Talc, 258 



Talchir conglomerate, 474 

 Talcose rocks, 291 

 Talus, 27, 74, 75 



