INDEX. 



609 



Onondagan fish, ii, 460 



formation, ii, 418, 424 



ganoids, ii, 461 



protozoans, ii, 467 



sharks, ii, 461 



sponges, ii, 467 



trilobites, ii, 467 

 Ontario (see Silurian) 

 Onychodus, ii, 463 

 Onyx, i, 471 

 Oolite, i, 435. 47 1» 496 

 Oolitic series, iii, 73 

 Ooze, i, 471 

 Opal, i, 465 



Opeche shale, iii, 68, 565, 566 

 Operculina, iii, 241 

 Ophileta complanata, ii, 353 



primordialis, ii, 299 

 Opis, iii, 91 



Opossums, Miocene, iii, 290 

 Orbitoides, iii, 241 

 Orbitolites, iii, 241 

 Ordovician annelids, ii, 361, 363 



Appalachian sections of, ii, 315 



brachiopods, ii, 355, 356 



bryozoans, ii, 357 



cephalopods, ii, 352 



classification of, ii, 310 



climate of, ii, 342 



ccelenterates, ii, 360, 361 



corals, ii, 360, 361 



crinoids, ii, 359 



Crustacea, ii, 35 1 



echinoderms, ii, 357, 359 



economic products of, ii, 336 



of Europe, ii, 338 



fauna, extra-Ameiican, ii, 367 



foreign, ii, 338 



gastropods, ii, 353, 354 



graptolites, ii, 344, 362 



igneous rocks of, ii, 322 



insect life of, ii, 346 



land life of, ii, 346 



lead in, ii, 337 



life, ii, 342, 343, 346 



manganese ore in, ii, 337 



New Brunswick, ii, 336 



Nova Scotia, ii, 336 



outcrops of, ii, 331 



pelecypods, ii, 354 



period, close of, 332 



period, formations and physi- 

 cal history of, ii, 304 



period, sedimentation of, ii,304 



phosphates of Tennessee, ii,337 



position of beds, ii, 322 



protozoa, ii, 361 



sections of, in interior, ii, 319 



sponges, ii, 363 



strata, condition of, ii, 324 



succession of faunas, ii, 364 



system, exposure of, ii, 326 



Taconic mountains, ii, 326 



thickness of, ii, 330 



trilobites, ii, 347. 351 



Upper, fauna, ii, 367 



Upper Mississippi section, ii, 

 313 



vertebrates, ii, 347 



western sections, ii, 322 



Ordovician, wide-spread lime- 

 stone of, ii, 321 



zinc in, ii, 337 

 Ore deposits (see Ores) 

 Ore regions, origin of, i, 477 

 Oregon, loess in, iii, 409 

 O'Reilly, J. P., cited, i, 538 

 Oreodons, Eocene, iii, 236 



Miocene, iii, 284 

 Oreopithecus, iii, 289 

 Ores, i,-428, 474-485 



concentration by reprecipita- 

 tion, i, 479 



concentration by solution, i, 

 479 



concentration by surface 

 leaching, i, 478 



" flaxseed," i, 497 



influence of rock walls on 

 deposition, i, 484 



magmatic segregation, i, 475 



marine segregation, i, 476 



original distribution, i, 475 



purification by leaching, i, 478 



residual concentration, i, 478 

 Organic processes, i, 638 



residue, i, 640, 641 



rocks, i, 449, 646 

 Organ-pipe coral, Silurian, ii, 407 

 Origin and descent of rocks, i, 



393-484 

 Original crust, ii, 84 



heat distribution, i, 559~568 



material of earth, importance 

 of, ii, 119 

 Oriskany brachiopods, ii, 458, 

 459 



corals, ii, 459 



crinoids, ii, 459 



fauna, ii, 451, 457 



fish, ii, 459 



formation, ii, 422 



mollusks, ii, 459 



trilobites, ii, 459 

 Ornithopoda, iii," 97 



Cretaceous, iii, 178 



Jurassic, iii, 99 

 Orogenic movements, i, 537 

 Orohippus, iii, 235 

 Orophocrinus stelliformis, ii, 525 

 Orthacanthus, ii, 614 

 Orthis, ii, 456, 472 



tricenaris, ii, 356 

 Orthoceras annulatocostatum, ii, 

 532 



annulatum, ii, 403, 409 



bilineatum, ii, 352 



blackei, iii, 53 



cribrosum, ii, 616 



Permian, ii, 655 



sociale, ii, 352 

 Orthoceratites, Triassic, iii, 56 

 Orthoclase, i, 400, 46s 

 Orthodesma rectum, ii, 354 

 Orthophyre, i, 471 

 Ortmann, A. E., cited, iii, 281 

 Orton, E., cited, ii, 336, 440, 



560 

 Ortonia minor, ii, 363 

 Osage blastoids, ii, 525 



Osage brachiopods, ii, 525 



coral, ii, 525 



crinoids, ii, 525 



echinoids, ii, 525 



fauna, ii, 522, 524 



formation, ii, 500, 501; iii, 

 558 



sponges, ii, 525 

 Osars, i, 306; iii, 374 

 Osborn, H. F., cited, ii, 647; 

 iii, 119, 207, 228, 237, 238, 

 255, 284 

 Osteolepis, ii, 489 

 Ostracoderms, ii, 537 



Devonian, ii, 482-486 

 Ostracodes, Devonian, ii, 490 



Silurian, ii, 408 

 Ostrea, iii, 82, 295 



carolinensis, iii, 292 



compressirostra, iii, 243 



deltoidea, iii, 83 



larva, iii, 189 



soleniscus, iii, 189 



strigilecula, iii, 92, 93 

 Ostreidae, iii, 134 

 Oswayo formation, ii, 557 

 Oswegan series, ii, 370, 371 

 Otoceras, iii, 49, 52 

 Otoccelus, ii, 650 

 Otozamites, iii, 39 



carolinensis, iii, 41 

 Oudenodon trigoniceps, iii, 42 

 Ouray limestone, ii, 506; iii, 573 

 Outcrops, effects of faults on, i, 



522 

 Outward flow of heat, and melt- 

 ing due to, ii, 102 

 Outwash plains, i, 306; iii, 372 



subaqueous, iii, 372 

 Overloading of streams, i, 177, 



178, 186 

 Overthrust, i, 518 



in Scotland, ii, 341 

 Overwash plains, iii, 372 

 Owen, R., cited, iii, 324 

 Oxbow lakes, i, 192, 198 

 Oxidation, i, 42, 427 

 Oxinea mortoni, iii, 187 

 Oxmoor sandstone, iii, 551 

 Oxydactylus, iii, 286 



JongipeS; iii, 287 

 Oxymeris, iii, 294 

 Oxyrhina, iii, 294 

 Oxytonia, iii, 91 

 Ozarkian period, iii, 311 

 Ozocerite, i, 465, 646 



Pachydiscus, iii, 134 



Pachynolophus, iii, 235 



Pacific coast, Comanchean, iii, 

 122 

 Cretaceous, iii, 160 

 Cretaceous fauna, iii, 190 

 Eocene, iii, 200 

 Liassic fauna, iii, 90 

 Lower Jurassic, iii, 61 

 Middle Jurassic, iii, 63 

 Middle Jurassic, fauna, iii, 91 

 Miocene, iii, 262 

 Pliocene, iii, 309 



