472 



INDEX 



Mountain range, 275. 

 Mountain system, 275. 

 Mountain, volcanic, 52, 280. 

 Mountains, 274. 



block, 276. 



combination, 281. 



destruction of, 282. 



distribution of, 275. 



faulted, 276. 



folded, 277. 



of circumdenudation, 281. 



of circumerosion, 281. 

 Movement of glaciers, 197. 

 Movements of sea, 235. 

 Mud, 258. 

 Mud cracks, 56. 



Narrows, 162. 

 Natural bridge, 118, 244. 

 Natural levee, 177. 

 Nautilus, 299. 

 Nebula, spiral, 312. 

 Nebular theory, 309. 

 Necks, volcanic, 52, 53. 

 Neutral rocks, 24. 

 Newark formation, 398. 

 Niagara fauna, 352. 

 Niagara formation, 351. 

 Normal faults, 71,73. 

 Nunataks, 203. 



Oblique lamination, 55. 

 Obsidian, 25, 31, 32. 

 Ocean deposits, 256. 

 Ocean, offices of, 234. 



shores of, 237. 

 Oceans, 233. 

 Olivine, 22. 



Onondaga limestone, 360. 

 Oolite, 260. 

 Ooze, 37, 258. 

 Ordovician deposits, 342. 

 Ordovician period, 339, 341. 

 Ore vein, 80. 

 Organic deposit, 258. 

 Oriskany sandstone, 360. 

 Ostracoderms, 365, 366. 



Outcrop, 18, 69. 

 Outliers, 357. 

 Outwash plains, 228. 

 Overthrusts, 73, 74. 

 Overturned folds, 67. 

 Ox-bow lake, 180. 

 Oxidation, 103. 

 Oxides, 19. 

 Oyster shell, 406. 



Paleontology, 9. 



Paleozoic Alps, 371. 



Palisades, 53. 



Peat, 269, 380. 



Pelecypods, 298, 345, 364, 399, 



406, 423. 



Peneplains, 147, 154. 

 Pennsylvanian period, 376. 

 Pennsylvanian plants, 382-384. 

 Pennsylvanian land animals, 385. 

 Peridotite, 29, 30. 

 Permian period, 389-392. 

 Petrification, 122. 

 Petroleum, 435. 

 Petrology, 9. 

 Phenacodus, 443. 

 Physical geology, 10. 

 Piedmont glaciers, 194, 202. 

 Piedmont plateau, 414. 

 Pitch, 70. 

 Pitchstone, 32. 

 Pitchstone-porphyry, 33. 

 Piracy of streams, 169. 

 Plains, 285. 



alluvial, 176. 



base-level, 147. 



classes of, 286. 



flood, 176, 182. 



origin of, 286. 



outwash, 228. 

 Planes, bedding, 54. 

 Planetesimal theory, 311. 

 Plants, 293. 



Comanchean, 416. 



and animals, Ordovician, 346. 



Pennsylvanian, 382. 

 Plateaus, 284. 



erosion of, 285. 



