fOLUME XXXI 



NUMBER 5 



THE 



JOURNAL OF Geology 



A Semi-Quarterly 



Edited By 

 thomas c. chamberlin 



With the Active Collaboration of 



ROLLIN T. CHAMBERLIN, Managing Editor 

 Dynamic Geology 

 STUART WELLER, Invertebrate Paleontology ALBERT JOHANNSEN, Petrology 



EDSON S. BASTIN, Economic Geology ' J- HARLEN BRETZ. Stratigraphic Geology 



ASSOCIATE EDITORS 



SIR ARCHIBALD GEIKIE, Great Britain 



CHARLES BARROIS, France 

 I ALBRECHT PENCK, Germany 

 |*HANS REUSCH, Norway 

 I GERARD DeGEER, Sweden 



SIR T. W. EDGEWORTH DAVID, Australia 



H. ALBERT BROUWER, Holland 

 i BAILEY WILLIS, Leland Stanford Junior University 



ARTHUR L, 

 * Deceased 



CHARLES D. WALCOTT, Smithsonian Institution 

 DAVID WHITE, U.S. Geological Survey 

 RICHARD A. F. PENROSE, Jr., PhUadelphia, 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 

 DAY, Carnegie Institution 



JULY-AUGUST 192^ 



THE MINERALOGRAPHY OF THE FELDSPARS, PART H, CONCLUDED 



Harold L. Alling 353 



SIGNIFICANT AMELIORATIONS OF PRESENT ARCTIC CLIMATES T. C. Chambeelin 376 



THE PHYSICAL CHEMISTRY OF THE CRYSTALLIZATION AND MAGMATIC DIFFER- 

 ENTIATION OF IGNEOUS ROCKS - - - - - - - J. H. L. VoGT 407 



THE TEMPORARY MISSISSIPPI RIVER - - - - - Walter H. SenoEWE 420 

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THE UNIVERSITY OF CHICAGO PRESS 



CHICAGO, ILLINOIS, U.S.A. 



THE CAMBRIDGE UNIVERSITY PRESS, Londok 



THE MARUZEN-KABUSHIKI-KAISHA, Tokyo, Osaka, Kyoto, Fukuoko, Sendai 



THE MISSION BOOK COMPANY, Shanghai 



