VOLUME XXVll 



THE 



NUMBER 6 



Journal of Geology 



A Semi-Quarterly 



Edited By 

 thomas c. chamberlin and rollin d. salisbury 



With the Active Collaboration of 



STUART WELLER, Invertebrate Paleontology ALBERT JOHANNSEN, Petrology 



ROLLIN T. CHAMBERLIN, Dynamic Geology 



ASSOCIATE EDITORS 



SIR ARCHIBALD GEIKIE, Great Britain 



CHARLES BARROIS, France 



ALBRECHT PENCK, Germany 



HANS REUSCH, Norway 



GERARD DeGEER, Sweden 



T. W. EDGEWORTH DAVID, Australia 



BAILEY WILLIS, Leland Stanford Junior University 



CHARLES D. WALCOTT, Smithsonian Institution 



JOSEPH P. IDDINGS, Washington, D.C. 



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, Harvard University 

 WILLIAM H. EMMONS, University of Minnesota 

 ARTHUR L. DAY, Carnegie Institution 



SEPTEMBER-OCTOBER 1919 



CRYSTALLIZATION-DIFFERENTIATION IN IGNEOUS MAGMAS - - N. L. Bowen 393 



THE RICHARDTON METEORITE T. T. Quirke 431 



PRE-CAMBRIAN ROCKS OF SOUTHEAST NEWFOUNDLAND - A. F. Buddington 449 



CURIOUS EROSION FEATURES IN WEST TENNESSEE CLAYS - Rolf A. Schroeder 480 



REVIEWS - - . - - - - - - - - - 482 



RECENT PUBLICATIONS 485 



THE UNIVERSITY OF CHICAGO PRESS 



CHICAGO, ILLINOIS, U.S.A. 



THE CAMBRIDGE UNIVERSITY PRESS, London and Edinburgh 



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



THE MISSION BOOK COMPANY, Shanghai 



