712 



INDEX 



Pliocene epoch — (Continued) 



migration during, 640-641. 



of Atlantic and Gulf coasts, 585-586. 



of other continents, 588-590. 



of Pacific coast, 587. 



physical geography of, 585-590. 



of western interior, 586. 

 Pliosaurus, 554. 

 Plucking by glaciers, 157. 



by ice sheets, 183. 

 Plugs, 316. 



Plutonic rocks, 324-332. 

 Plymouth, England, storm waves at, 



201. 

 Pbebrotherium, 616. 

 Polypora lilaea, 458. 

 Porphyry, 331. 

 Portage stage, 452, 454. 

 Portheus, 534, 535. 

 Port Jackson shark, 463. 

 Postglacial stage, 649. 

 Potato Creek, effect of deforestation on, 



97- 

 Potholes, 93-95. 

 Potomac formation, 514. 

 Pottsville stage, 472. 

 Powers, S., 342. 



Pre-Cambrian formations, 388-400. 

 Precession of equinoxes and climate, 



661. 

 Precipitation of ores, 372. 

 Predentata, armored, 539, 545-549. 

 Predentata, unarmored, 539, 544-545. 

 Prehistoric man, 674-680. 

 Pressure, lateral, 359. 

 Primates, 622-623. 

 Procamelus, 617. 

 Productella spinulicosta, 458. 

 Productus, 481. 

 Productus burlingtonensis, 482. 



costatus, 482. 

 Proterozoic era, 393 - 399- 



climate of, 398. 



contrasted with Archaeozoic, 393. 



duration of, 397. 



fossils of, 396-397. 



glaciation of, 398. 



iron and copper of, 396. 



life of, 396-397- 



of Black Hills, South Dakota, 395- 

 396. 



of Grand Canyon, Arizona, 394-395. 



of Lake Superior region, 393. 



Proterozoic era — (Continued) 



in other continents, 396. 



unconformities of, 394. 



volcanic activity of, 394. 

 Protoceras, 619. 

 Protocetus, 596. 

 Protohippus, 610. 

 Protorohippus, 609. 

 Protowarthia cancellata, 434. 

 Protozoans, Cambrian, 416. 



Carboniferous, 480. 



Ordovician, 427. 

 Protylopus, 616. 

 Prozeuglodon, 596. 

 Pteranodon, 559-560. 

 Pteraspis, 450. 

 Pteridosperms, 492-493. 

 Pterinea demissa, 433. 



emacerata, 447. 



flabellum, 459. 

 Pteropods, Cambrian, 413. 



Silurian, 447. 

 Pterosaurs, 558-560. 

 Ptilodus, 591. 

 Puerco formation, 591. 

 Pulaski stage, 422. 

 Pumice, 297. 

 Pumiceous lava, 302. 

 Pyrite, 686. 



weathering of, 37. 

 Pyropsis bairdi, 528. 

 Pyrrhotite, 687. 



Quartz, 689. 



Quartzite, 248, 344, 350. 

 Quaternary period, 573, 643-684. 

 Quebec, landslide at, 73. 



Race, tidal, 201. 



Radioactivity and interior of the earth, 



274. 

 Radiolaria, 427. 

 Radiolarian ooze, 242. 

 Radiolites, 527. 

 Radiolites cornu-pastoris, 527. 

 Rain, mechanical effect of, 33, 34. 



effect on heated rocks, 33. 

 Raindrop impressions, 236. 

 Raised beaches, 214. 

 Raphinesquina alternata, 432. 

 Receptaculites, 445. 



