VOLUME XXX 



NUMBER 8 



THE 



Journal of Geology 



A Semi-Quarterly 



• L 



ii^^ 



*\5' 



EDITED BY i^ APK Z6 IL. 



THOMAS C. CHAMBERLI 



With the Active Collaboration of 



5&2!^AL.MO«^ 



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 



ALBRECHT PENCK, Germany 



HANS REUSCH, Norway 



GERARD DeGEER, Sweden 



SIR T. W. EDGEWORTH DAVID, Australia 



BAILEY WILLIS, Leland Stanford Junior University 



CHARLES D. -WALCOTT, Smithsonian Institution 



♦Deceased. 



*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 Umversity 

 WILLIAM H. EMMONS, University of Minnesota 

 ARTHUR L. DAY, Carnegie Institution 



NOVEMBER-DECEMBER 1922 



THE PHYSICAL CHEMISTRY OF THE CRYSTALLIZATION AND MAGMATIC DIFFER- 

 ENTIATION OF IGNEOUS ROCKS - - - J. H. L. Vogt 659 



THE PLEISTOCENE HISTORY OF THE LOWER WISCONSIN RIVER Paul MacClintock 673 



ORIGIN OF THE TRIASSIC TROUGH OF CONNECTICUT - - |Wilbtjr G. Foye 690 



■IN SUPPORT OF GARDNER'S THEORY OF THE ORIGIN OF CERTAIN CONCRETIONS 



Leroy Patton 700 



MUD CRACKS ON STEEPLY INCLINED SURFACES - - - Gerald R. MacCarthy 702 



PETROLOGICAL ABSTRACTS AND REVIEWS - - - - - - - - - 703 



REVIEWS ----------------- 717 



INDEX -----------.-----,- 725 



THE UNIVERSITY OF CHICAGO PRESS 



CHICAGO, ILLINOIS, U.S.A. 



THE CAMBRIDGE UNIVERSITY PRESS, London 



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



THE MISSION BOOK COMPANY, Shanghai 



