INDEX 



967 



Niagaran coral reefs, 541 



fauna, 548 



series, 537, 538 

 Niobrara formation, 746 

 Nipissing Lakes, 881 

 Nodosaria bacillum, 795 



communis, 795 

 Nodules, 85 



Noeggerathiopsis hislop, 671 

 Non-glacial Quaternary formations, 



899 



Non-placental mammals, 793 

 Nordenskjold, A. E., 818 

 Normal fault, 02 

 Northern Interior coal field, 625 

 Novaculite, 85 

 Nova Scotian coal-field, 626 

 Nucula ovula, 797 



storrsi, 741 



Nucleocrinus verneuli, 581 

 Number of coal beds, 636, 641 

 Nummulites, 794 

 Nummulitic limestone, 782 

 Nyctosaurus gracilis, 765 



Oakville beds, 807 

 Oblique fault, 65 

 Obsidian, 20, 61, 85, 379 

 Ocean basins, 8, 317 

 origin of, 433 

 relief of, 9 

 shape of, 290 



Ocean bed, topography of, 290 

 Ocean currents, 296 



work of, 315 

 Ocean, work of, 289 

 Oceanic dimensions, 6 



era, 427 

 Ocher, 78 



Odontocephalus segeria, 581 

 Odontopteris cornuta, 645 

 Oenonites rostratus, 533 

 Offset, 65 

 Ohio shale, 567 

 Oil and gas in Devonian, 571 

 in Illinois, 639 

 Kansas, 639 

 New York, 571 

 Ohio, 517 

 Oklahoma, 639 

 Ontario, 572 

 Pennsylvania, 571 

 the Pennsvlvanian, 639 

 West Virginia, 572 

 Oil in California, 808 



Oil continued 



in Cretaceous of Texas, 746 



in Illinois, 600 



Potts ville conglomerate, 620 

 Texas, 807 

 Oilstone, 85 



Oklahoma, oil and gas in, 639 

 Old age of valleys, 132 

 Old Faithful, 218 

 Old Red Sandstone, 573, 590 

 Oldest accessible rocks, 438 

 Oldham, R. D., 349, 350, 817 

 Olenellus Cambrian, 482 



fauna, 482 

 Olenoides curticei, 496 



fauna, 483 



Oligocene Bad Lands, 799 

 Oligocene formations, 797 

 Oligocene period, 772, 797 



deformative movements in, 801 



igneous activity of, 800 



life of, 801 



of Caribbean region, 799 



of Europe, 799 

 Oligoclase, 79 

 Oligoporus mutatus, 609 

 Oliva litterata, 826 

 Olivene, 76, 79 

 Oncoceras pandion, 525 

 Oneida conglomerate, 537 

 Onondaga fauna, 579 



formation, 559, 561 

 Onyx, 80, 85 

 Oolite, 46, 48, 85 

 Oolitic limestone, 709 

 Oozes, 37, 85, 316, 326, 329 

 Ophileta primordalis, 498 

 Orange Sand, 829 

 Ordovician period, 507 



climate of, 520 



close of, 515 



duration of, 520 



faunas, 534, 535, 



limestone, extent of, 510 

 Ordovician of Arctic region, 521 



of Europe, 518 

 New York, 509 

 Tennessee, 510 

 the west, 511 

 Wisconsin, 510 



outcrops of, 514, 515 



plants, 534 



sections of, 509, 512 

 Ore, 68 



regions, origin of, 70 



