VOLUME XXVll 



NUMBER 4 



THE 



Journal of Geology 



A Semi-Quartehly 



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 



MAY-JUNE 1919 



THE BUILDING OF THE COLORADO ROCKIES. II - - - Rollin T. Chamberlin 225 



NOTES ON PRINCIPLES OF OIL ACCUMULATION - - - - Alex. W. McCoy 252 



SOME STRATIGRAPHIC AND STRUCTURAL FEATURES OF THE PRE-CAMBRIAN 



OF NORTHERN QUEBEC. Ill - H. C. Cooke 263 



A PLANIMETER METHOD FOR THE DETERMINATION OF THE PERCENTAGE 



COMPOSITIONS OF ROCKS Albert Johannsen 276 



GEOLOGY OF FLORIDA - - E. H. Sell.ards 286 



RECENT PUBLICATIONS - . . 303 



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 MISSIO.V BOOK COMPANY, Shanghai 



