5 66 



INDEX 



Orthoptera, 402, 424, 442, 465. 

 Orthorhombic system of crystals, 10. 

 Osage stage, 409, 411. 

 Ostracoda, 373, 382, 424. 

 Ostracoderms, Devonian, 403; Ordovi- 



cian, 384; Silurian, 393. 

 Ostrea, 465, 488, 489*, 504*. 

 Otozamites, 449, 451*. 

 Otters, fossil, 517. 



Ouachita Mountains, 333, 334, 439. 

 Outcrop, 233. 

 Outlier, 319 ; faulted, 320. 

 Overlap, 271*. 

 Overturned folds, 237*, 239. 

 Overwash plain, 312, 528. 

 Owen's Valley, earthquake of, 63. 

 Owls, fossil, 503, 516. 

 Oxen, fossil, 522. 

 Oxidation of minerals, 73. 

 Oxycsna, 505. 



Pachy/ENA, 505. 



Pacific coast, Pleistocene submergence, 



533- 

 Palaeocrinoidea, 424, 441, 450. 

 Palseoechinoidea, 441, 450. 

 Palaeogene, 497. 

 Palceohatteria, 435. 

 Palceoniscus, 426. 

 Palceosyops, 506. 

 Palceozamia, 462. 

 Palaeozoic era, 355, 365^ 

 Palisades of Hudson, 82, 280, 281* 282*. 

 Palms, fossil, 486, 502, 508, 516. 

 Palustrine deposits, 132. 

 Pampas, loess of, 125. 

 Panthers, fossil, 517. 

 Paradoxides, 372 ; Fauna, 368. 

 Paramorphic minerals, 290. 

 Parrots, fossil, 516. 

 Partings (of coal seams) , 412. 

 Patagium, 472. 

 Patagonia, glaciation of, 537. 

 Patagonian series or stage, 523. 

 Peat, i33t, 215. 

 Peat bogs, 133, 134, 135 ; theory of coal 



formation, 213. 

 Pebbles, river, 137 ; wind cut, 86. 

 Peccaries, fossil, 509, 522, 538. 

 Pecopte?is t 423*, 432. 

 Pecten, 451, 504*. 



Pedio7?iys, 493. 



Pelagic deposits, 176. 



Pelicans, fossil, 503, 516. 



Pelycypoda, see Bivalves. 



Peneplain, 3iof, 319, 323, 341 ; Kitta- 

 tinny, 342 ; Shenandoah, 342. 



Pentacrinus ; 463*, 464. 



Peiitameridce, 391. 



Pentamerus , 393, 425. 



Pentremites ; 419*, 422. 



Perchcerzcs, 509. 



Peridotite, 202. 



Period, geological, 354. 



Perisphinctites, 467. 



Perissodactyla, 505, 506, 509. 



Perlite, 197. 



Permian period, 355, 428I-. 



Permo-Carboniferous, 436. 



Petrifaction, 346, 347. 



Petrography, 194. 



Phacops, 391, 400, 401*. 



Phascolotherium, 473. 



Phenocrysts, 190. 



Phillips as trcea, 400. 



Phillipsia, 419*, 424, 432. 



Pholadomya, 466. 



Phonolite, 199^ 284. 



Phosphate deposits, 130. 



Phragmoceras, 392*, 393, 402. 



Phragmocone (of Belemnites) , 467. 



Phyllite, 294. 



Phylloceras, 466. 



Phyllograptus, 383*. 



Phyllopoda, 373, 382, 424. 



Phyllotheca, 437. 



Piedmont glaciers, no. 



Pinacoceras, 452. 



Pines, fossil, 502. 



Pinites, 462. 



Pipes, 89. 



Pirsson, L. V-, 202. 



Pisolite, 209. 



Pitchstone, 197. 



Placenticeras, 488. 



Plagioclase, ijf, 198, 202, 358. 



Plain, of marine denudation, 304 ; over- 

 wash, 312, 528; of subaerial denuda- 

 tion, 310, 319, 323. 



Planorbis, 504*. 



Plants, Cambrian, 371 ; Carboniferous, 

 418 ; Cenozoic, 495 ; Cretaceous, 485 ; 



