VOLUME XXVll NUMBER 7 



THE 



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 JOHN C. BRANNER, Leland Stanford Junior University 



CHARLES BARROIS, France RICHARD A. F. PENROSE, Jr., Philadelphia, Pa. 



ALBRECHT PENCE, Germany WILLIAM H. HOBBS, University of Michiga^ 



^t^^.^^^J^r^-Z°T^. FRANK D. ADAMS, McGill University 



CHARLES K. LEITH, University of Wisconsin 



GERARD DeGEER, Sweden 



T. W. EDGEWORTH DAVID, Australia 



BAILEY WILLIS, Leland Stanford Junior University WALLACE W. ATWOOD, Harvard University 



CHARLES D. WALCOTT, Smithsonian Institution WILLIAM H. EMMONS, University of Minnesota 



JOSEPH P. IDDINGS, Washington, D.C. ARTHUR L. DAY, Carnegie Institution 



OCTOBER-NOVEMBER 1919 



THE LATE PLEISTOCENE SUBMERGENCE IN THE COLUMBIA VALLEY OF OREGON 



AND WASHINGTON - - J Harlen Beetz 489 



A LABORATORY AND FIELD STUDY OF COBBLE ABRASION Chester K. Wentworth 507 



CLASSIFICATION OF SPRINGS Kirk Bryan 522 



AEQUINOCTIA, AN OLD Px\LEOZOIC CONTINENT - - - - E. C. Abendanon 562 



ON COARSE GABBROID DIABASE IN WESTFIELD, MASSACHUSETTS 



Earl V. Shannon 579 



RECENT PUBLICATIONS - 582 



THE UNIVERSITY OF CHICAGO PRESS 



CHICAGO, ILLINOIS, U.S.A. 



THE CAMBRIDGE UNIVERSITY PRESS, London 



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



THE MISSION BOOK COMPANY, Shanghai 



