VOLUME XXIV 



THE 



NUMBER 3 



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 JOHANNSENT, Petrology 



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



ALBERT D. BROKAW, Economic Geology 



ASSOCIATE 

 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 

 GROVE K. GILBERT, Washington, D.C. 

 CHARLES D. WALCOTT, Smithsonian Institution 

 HENRY S. WILLIAMS, Cornell University 



EDITORS 



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 



APRIL-MAY 1916 



ORVILLE A. DERBY j 0H n C. Branner 209 



TYPES OF PRISMATIC STRUCTURE IN IGNEOUS ROCKS - - Robert B. Sosman 215 

 ELLIPSOIDAL LAVAS IN THE GLACIER NATIONAL PARK, MONTANA 



Lancaster D. Burling 235 

 THE ORIGIN OF RED BEDS.. A STUDY OF THE CONDITIONS OF ORIGIN OF THE 

 PERMOCARBONIFEROUS AND TRIASSIC RED BEDS OF THE WESTERN 



UNITED STATES. PART II ------ C. W. Tomlinson 238 



THE ACADIAN TRIASSIC. PART III ------ Sidney Powers 254 



THE LOMBARD OVERTHRUST AND RELATED GEOLOGICAL FEATURES 



WlNTHROP P. HAYNES 269 



THE SKELETON OF TRIMERORHACHIS - - - - - - S. W. Williston 291 



REVIEWS - - 298 



RECENT PUBLICATIONS , - - - - 310 



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 



THE MISSION BOOK COMPANY, Shanghai 



