VOLUME XXII 



NUMBER 5 



THE 



Journal of Geology 



A Semi-Quarterly 



Edited By 



THOMAS C. CHAMBERLIN AND ROLLIN D. SALISBURY 

 With the Active Collaboration of 



SAMUEL W. WILLISTON 



Vertebrate Paleontology 



STUART WELLER 



Ipvertebrate Paleontology 



ALBERT JOHANNSEN 

 Petrology 



WALLACE W. ATWOOD 

 Physiography 



WILLIAM H. EMMONS 



Economic Geology 



ROLLIN T. CHAMBERLIN 

 Dynamic Geology 



ASSOCIATE EDITORS 



SIR ARCHIBALD GEIKIE, Great Britain 

 *HEINRICH ROSENBUSCH, Germany 

 *THEODOR N. TSCHERNYSCHEW, Russia 



CHARLES BARROIS, France 



ALBRECHT PENCK, Germany 



HANS REUSCH, Norway 



GERARD DeGEER, Sweden 



ORVILLE A. DERBY, Brazil 



T. W. EDGEWORTH DAVID, Australia 



BAILEY WILLIS, Argentine Republic 



♦Deceased. 



GROVE K. GILBERT, V^^ashington, D.C. 

 CHARLES D. WALCOTT, Smithsonian Institution 

 HENRY S. WILLIAMS, Cornell University 

 JOSEPH P. IDDINGS, Washington, D.C. 

 JOHN C. BRANNER, Leland Stanford Junior University 

 RICHARD A. F. PENROSE. Jr.. Philadelphia, Pa. . 

 WILLIAM B. CLARK, Johns Hopkins University 

 WILLIAM H. HOBBS, University of Michigan 

 FRANK D. ADAMS, McGill University 



CHARLES K. LEITH, University of Wisconsin 



t 



JULY-AUGUST 1914 



THE STRENGTH OF THE EARTH'S CRUST.' y. ±UE DEPTH OF MASSES PRO- 

 DUCING GRAVITY ANOMALIES AND DEFLECTION RESIDUALS 



Joseph Barrel! 



CERTAIN TYPES OF STREAM VALLEYS AND THEIR MEANING John Lyon Rich 



STREAM PIRACY AND NATURAL BRIDGES IN THE LOESS OF SOUTHEAST 

 MISSOURI C. L. Dake 



CRYSTALLOBLASTIC ORDER AND MINERAL DEVELOPMENT IN METAMORPHISM 



Frederic H. Lahee 



DLASTROPHISM AND THE FORMATIVE PROCESSES. VIII. THE QUANTITATIVE 

 ELEMENT IN CIRCUM- CONTINENTAL GROWTH - - - T. C. Chamberlin 



PETROLOGICAL ABSTRACTS AND REVIEWS 

 RECENT PUBLICATIONS - - - - 



441 

 469 



498 



500 



516 

 529 

 534 



THE UNIVERSITY OF CHICAGO 



CHICAGO, ILLINOIS, U.S.A. 



PRESS 



Agents 



THE CAMBRIDGE UNIVERSITY PRESS, London and Edinburgh 



KARL W. HIERSEMANN, Leipzig 



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



