NUMBER 6- 
: EDITED BY 
THOMAS ne CHAMBERLIN AND ROLLIN 
| With the Active Collaboration of 
ALBERT JOHANNSEN, Petrology 
ROLLIN T. CHAMBERLIN, Dynamic Geology 
ASSOCIATE EDITORS 
; JOHN C. BRANNER, Leland Stanford Junior University 
; RICHARD A. F. PENROSE, Jr., Philadelphia, Pa. 
, WILLIAM H. HOBBS, University of Michigan 
FRANK D. ADAMS, McGill University 
CHARLES K. LEITH, University of Wisconsin 
WALLACE W. ATWOOD, Clark University ~ 
WILLIAM H. EMMONS, University of Minnesota 
ARTHUR L, DAY, Carnegie Institution 
_ SEPTEMBER-OCTOBER 1921 . y 
: CONSIDERATIONS OF THE GENESIS OF ORE DEPOSITS care 
& R. H. RASTALL 487 sre 
OM TA POSSIBLE FACTOR IN CHANGES OF GEOLOGICAL CLIMATE 
HARLOW SHAPLEY 502. 
- - - -  - .- Morris M. ‘Leicuton 583 
- - - - - ae ae ¥ Voct 515 
OF ER OSION IN THE PIEDMONT PROVINCE OF PENNSYLVANIA - F. BAscom 540 
ie 2 “A ig th - - - - H. A. BROUWER 560 
Ct wae SOP EN SA Oe) Cue Pe ei, | CaM ae a eae 
Ber age ar mes) Ais gets ance Pama ane ee 
HE "UNIVERSITY OF CHICAGO: PRESS 
CHICAGO, ILLINOIS, U. S. A. 
Af 
uae ‘THE CAMBRIDGE ‘UNIVERSITY PRESS, Lonpon 
THE p MARUZEN-KABUSHIKI-KAISHA, Toxyo, Osaka, Kyoto, FUKUOKA, SENDAI 
deer Sonos TPE MISSION BOOK CO SHANGHAI 4 
