VOLUME XXI II 



THE 



NUMBER 7 



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 



Invertebrate Paleontology 



ALBERT JOHANNSEN 



Petrology 

 ROLLIN T. CHAMBERLIN 



Uynamic Geology 



ASSOCIATE EDITORS 



SIR ARCHIBALD GEIKIE, Great Britain 



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 



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, McGlll University 

 CHARLES K. LEITH, University of Wisconsin 

 WALLACE W. ATWOOD, Harvard University 

 WILLIAM H. EMMONS, University of Minnesota 



OCTOBER-NOVEMBER 191 5 



REVISION OF PRE-CAMBRIAN CLASSIFICATION IN ONTARIO 



WiLLET G. Miller and Cyril W. Knight 585 



MET AMORPHIC STUDIES. CONVERGENCE TO MINERAL TYPE IN DYNAMIC 



METAMORPHISM - - C. K. Leith and W. J. Mead 600 



THE AGE OF THE CRETACEOUS FLORA OF SOUTHERN NEW YORK AND NEW 



ENGLAND Edward W. Berry 608 



A CRITICAL STUDY OF THE FOSSIL BIRD GALLINULOIDES WYOMINGENSIS 



EASTMAN - - R. W. Shufeldt 619 



GROUND-ICE WEDGES. THE DOMINANT FORM OF GROUND-ICE ON THE NORTH 



COAST OF ALASKA - - E. De K. Leffingwell 635 



STRATIGRAPHY OF THE WAVERLY FORMATIONS OF CENTRAL AND SOUTHERN 



OHIO. PART I Jesse E. HydfI 655 



RECENT PUBLICATIONS ...--. 683 



THE UNIVERSITY OF CHICAGO PRESS 



CHICAGO, ILLINOIS, U.S.A. 



Agents 



THE CAMBRIDGE UNIVERSITY PRESS, London and Edinburgh 



KARL W. HIERSEMANN, Leipzig 



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



