INDEX 



701 



Ocean basins, continued 



topography of, 6, 168 

 Ocean life, 169 

 ( )iv;m water, 167 



movements of, 1 73 

 Oceanic era, 307 

 Odontocephalus segeria, 416 

 Odontopteris cornuta, 460 

 Oenonites rostratus, 386 

 Ohio gas and oil, 374 

 Oil and gas, Devonian, 410 



Miocene, 583 



Ordovician, 374 



Pennsylvanian. 454 

 Old age, topographic, 72 

 Old Red Sandstone, 411, 421 

 Oldest rocks, 316 

 Olenellus fauna, 348 

 Olenellus gilberti, 348 

 Olenoides curticei, 359 

 Olenoides fauna, 349 

 Oligocene, marine life, 580 

 Oligocene of Europe, 576 

 Oligocene period, 556, 574-580 



plants, 578 



Oligoporus mutatus, 434 

 Oliva litterata, 597 

 Olivine, 255 

 Oncoceras pandion, 380 

 Oneida conglomerate, 388 

 Onondaga fauna, 415, 416 



limestone, 402, 404, 405 

 Onyx, 254 

 Oolite, 289 

 Ooze, 197, 268 

 Ophileta primordalis, 361 

 Orange sand, 600 

 Ordovician igneous rocks, 370 

 Ordovician in Europe, 375 

 Ordovician land life, 387 

 Ordovician period, 367-387 



climate 01, 376 



close of, 373 



duration of, 376 



life, 376 



plants, 386 

 Ordovician rocks, changes in, 371 



outcrops of, 371, 372 



thickness of, 371 

 Ordovician, sections of, 368 

 Ordovician sedimentation, 367 

 Ore, 40 



Ore deposits, 40 

 Ore regions, origin of, 44 

 Ores, concentration of, 44 



Ores, continued 



location of, 46 

 Organic deposits, 193, 197, 198 



terrestrial, 652 

 Original crust, 308 

 Oriskany fauna, 415 

 Oriskanian series, 402, 404 

 Orogenic movements, 218 



Cretaceous, 541 



Jurassic, 505 



Permian, 475 

 Orohippus, 569 

 Orthis tricenaria, 382 

 Orthoceras annulato-costatum, 437 



annulatum, 397 



bilineatum, 380 



blakei, 500 



Cretaceous, 555 



cribrosum, 469 



rushensis, 481 



sociale, 380 

 Orthoclase, 254 

 Orthopters, 467 

 Orton, E., cited, 374 

 Osage fauna, 433, 435 

 Osage series, 426, 427 

 Osborn, H. F., cited, 567 

 Ostracoderms, 421, 440 

 Ostrea carolinensis, 595 



compressirostra, 573 



deltoidea, 510 



soleniscus, 554 



strigilecula, 512 

 Oswegan epoch, 388, 389 

 Ouachita Uplift, 373 

 Oudenodon trigoniceps, 495 

 Outcrops, width of, 353, 354 

 Outwash plains, 165 

 Ox-bow lakes, 115 

 Oxidation, 23 



Palaeaster simplex, 384 

 Palaeocaris typus, 466 

 Palaeohatteria longicaudata, 479 

 Pabeoneile constricta, 419 

 Palaeophonus caledonicus, 401 

 Palaeospondylus gunni, 422 

 Paleolithic age, 670 

 Paleozoic era, close of, 475 

 Paradoxides, 348 

 bohemicus, 348 

 Paralegoceras newsomi, 469 

 Paraphorynchus striatocostatus, 433 

 Parasmilia texana, 530 

 Pareiasaurus, 478 



