INDEX 



703 



glaciers in western moun- 

 tains, 657 



life, 663 



period, 613-676 

 1'U-Mosaurs, 514 



Cretaceous, 550 

 Plesiosaurus dolichodeirus, 514 

 Pleurocystis filitextus, 384 

 Plcurotoma potomacensis, 573 



lysoni, 573 



Pteurotomana nodulostriata, 437 

 Pliocene diastrophism, 604 



formations, marine, 604 



life, 608, 6n 



of Europe, 608 



period, 599-612 



plants, 608 



volcanic activity, 607 

 Pliohippus, 592 

 Plutonic rocks, 227, 245 

 Pocono formation, 426 

 Polar glaciers, 127 

 Polygyra clausa, 644 



monodon, 644 



multilineata, 644 

 Polynices duph'catus, 597 

 Polypora lilaea, 414 

 Ponding of streams, 107 

 Popanoceras walcotti, 481 

 Porphyry, 248, 251, 259, 262 

 Porphyritic texture, 249 

 Portage beds, 402 

 Poterioceras apertum, 380 

 Potomac River, 105 

 Potomac series, 523 

 Potsdam epoch, 344, 346 

 Pottsville Conglomerate, 441. 443 

 Prase, 254 

 Precipitation, 28 

 Precipitation from solution, 24 

 Prestwichia danae, 466 

 Primates, 571 



Miocene, 594 



Pliocene, 610 

 Prinotropis woplgari, 554 

 Proboscidians in America, 667 

 Proboscidians, Pliocene, 610 

 Prodromites gorbyi, 433 

 Productella pyxidata, 433 



spinulicosta, 416 

 Productive coal-fields, 443 

 Productus, 436, 438 



arcuatus, 433 

 burlingtonensis, 435 

 costatus, 469 



Productus continued 



fasciculatus, 437 



marginicinctus, 437 



nebrascensis, 469 



symmetricus, 469 

 Proetus ellipticus, 433 



parviusculus, 378 

 Profiles of valleys, 112 

 Progonoblattina columbiana, 466 

 Prosser, C. S., cited, 443 

 Proterozoic climate, 342 

 Proterozoic era, 325 



duration of, 337 



Proterozoic glacial formations, 342 

 Proterozoic life, 342 

 Proterozoic rocks, composition of, 325, 



32.7 329 



distribution of, 328, 331, 341 



origin of, 327 



relations to Archean, 325, 330 



structure of, 329 

 Proterozoic, subdivisions of, 326 

 Protocardia levis, 573 

 Protohippus, 592 

 Protospongia maculosa, 386 

 Protowarthia cancellata, 381 

 Protozoans, Pennsylvanian, 468 

 Pseudomonotis curta, 512 



hawni, 481 



Pseudomorph, 258, 287 

 Psychozoic era, 683 

 Pteridophytes, 458 

 Pteridosperms, 458 

 Pterinea demissa, 381 



emacerata, 397 



flabella, 419 

 Pterodactyls, 519 



Cretaceous, 550 

 Pterodactylus spectabilis, 519 

 Pteropod ooze, 199 

 Pterosaurs, 518 



Pterygometopus callicephalus, 378 

 Pterygotus, 400 



angh'cus, 401 



Ptychoceras crassum, 554 

 Ptycoparia kingi, ^59 

 Puget series, 559 

 Puget Sound depression, 559 

 Pugnax uta, 469 

 Pulpit-rocks, 179, 181 

 Pumice, 250, 258, 263 

 Pupa vermilionensis, 466 

 Pyrite, 258 



Pyroclastic rocks, 229, 235, 250 

 Pyropsis bairdi, 554 



