656 E. O. ULRICH INDEX TO "REVISION OF PALEOZOIC SYSTEMS" 



Page Plate 



Pennsylvania, Formations of northeastern • • 27, 29 



basin, Northeastern 562, 563 



Formations of central • • 27 



Pennsylvanian 29 



Comparison of, with other systems 607 



Period, Time value of geological 602 



Periodic revivals of erosion processes 313 



Periodicity in geologic history 595 



of diastrophie movements 393, 401 



Periods of folding, Relative importance of 436 



Permanence of earth features 603 



poles • • 406 



Perryville limestone ......... 416 27 



Petroleum and gas pools, Controlling conditions in . ' 335 



Phelps sandstone • • 29 



Phillips, John, Stratigraphic classification by • • 26 



Phyllograptus and Tetragraptus faunas, Age of 670 



Phyllograptus angustif olius '■ 668 



ilicifolius 668 



ilicifolius zone : 670 



typus var. nov 678 . * 



typus zone 652 



Phyllopods, Distribution of 504 



Pierce . . 27 



Piloceras 630 



newton-winchelli 639 



Pitkin limestone 530 29 



Platteville limestone . . 27 



Plattin limestone 27 



Platyceras minutissimum Walcott 503 



Platystrophia bed 311 



Platystrophia biforata 508, 509 



at Cincinnati, Ohio, and Madison, Indiana 5X)9 



lynx 509, 514 



Plectambonites sericeus 299, 508, 514, 519 



Plethospira cassina 668 



Pleurotomaria canadensis Billings 653 



Pocahontas formation 29 



Pocono sandstone . . 29 



Poles, Permanence of 406 



Polk Bayou, Upper . . 28 



Polk Creek shale 677 



Polypora varsoviensis 594 



Polytoechia 663 



Porambonites 502 



Portage formation . . 28 



Port Clarence limestone 643 



Port Ewen ■ 28 



