

THE 



JOURNAL OF GEOLOGY 



A Semi-Quarterly Magazine of Geology and 

 Related Sciences 



EDITED BY 

 THOMAS C. CHAMBERLIN AND *ROLLIN D. SALISBURY 

 With the Active Collaboration of 



STUART WELLER, 



Invertebrate Paleontology 



EDSON S. BASTIN 



Economic Geology 



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 



SIR T. W. EDGEWORTH DAVID, Australia 



BAILEY WILLIS, Leland Stanford Junior 



University 

 CHARLES D. WALCOTT, Smithsonian 



Institution 



*Deceased. 



*JOHN C. BRANNER, Leland Stanford Junior Uni- 

 versity 

 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 Minne- 

 sota 

 ARTHUR L. DAY, Carnegie Institution 



VOLUME XXX 



JANUARY-DECEMBER, 1922 



THE UNIVERSITY OF CHICAGO PRESS 

 CHICAGO, ILLINOIS 



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