t VOLUME XXIV 



THE 



NUMBER 6 



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 ALBERT JOHANNSEN, Petrology 



STUART WELLER, Invertebrate Paleontology ROLLIN T. CHAMBERLIN, Dynamic Geology 



ALBERT D. BROKAW, Economic Geology 



ASSOCIATE EDITORS 



SIR ARCHIBALD GEIKIE, Great Britain 



CHARLES BARROIS, France 



ALBRECHT PENCK, Germany 



HANS REJJSCH, Norway 



GERARD DeGEER, Sweden 



T. W. EDGEWORTH DAVID, Australia 



BAILEY WILLIS, Leland Stanford Junior University 



GROVE K. GILBERT, Washington, 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 

 WALLACE W. ATWOOD, Harvard University 

 WILLIAM H. EMMONS, University of Minnesota 

 ARTHUR L. DAY, Carnegie Institution 



SEPTEMBER-OCTOBER 1916 



THE PRE-WISCONSIN DRIFT OF NORTH DAKOTA - - - A. G. Leonard 521 



EVOLUTION OF THE BASAL PLATES IN MONOCYCLIC CRINOIDEA CAMERATA. II 



Herrick E. Wilson 533 



DIFFERENTIATION IN INTERCRUSTAL MAGMA BASINS - - Alfred Harker 554 



STRATIGRAPHY OF THE SKYKOMISH BASIN, WASHINGTON ' - Warren S. Smith 559 



"PUFF" CONES ON MOUNT USU Y. Oinouye 583 



ORIGIN OF FOLIATION IN THE PRE-CAMBRIAN ROCKS OF NORTHERN NEW 



YORK ----------- William J. Miller 587 



THE COMPOSITION OF THE AVERAGE IGNEOUS ROCK - - Adolph Knopf 620 



REVIEWS ------------ 623 



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, Fukuoka, Sendai 



THE MISSION BOOK COMPANY, Shanghai 



