XLbc S^ournal of (3eoloo^ 



Vol. XXIII CONTENTS FOR SEPTEMBER-OCTOBER J9J5 No. 6 



SOME EVENTS IN THE EOGENE HISTORY OF THE PRESENT COASTAL AREA OF THE GULF OF 



MEXICO IN TEXAS AND MEXICO E. T. Dumble 481 



THE STRENGTH OF THE EARTH'S CRUST (.Concluded). VIII. PHYSICAL CONDITIONS CONTROLLING 



THE NATURE OF LITHOSPHERE AND ASTHENOSPHERE (Section B) - - - Joseph Barrell 499 

 POPOSAURUS GRACILIS, A NEW REPTILE FROM THE TRIASSIC OF WYOMING - - M. G. Mehl 516 



THE CANNONBALL MARINE MEMBER OF THE LANCE FORMATION OF NORTH AND SOUTH DAKOTA 



AND ITS BEARING ON THE LANCE-LARAMIE PROBLEM - E. Russell Lloyd and C. J. Hares 523 



VARIATIONS OF GLACIERS. XIX - - - Harry Fielding Reid 548 



A NEW GENUS AND SPECIES OF AMERICAN THEROMORPHA. MYCTEROSAURUS LONGICEPS 



S. W. WiLLISTON 554 



USE OF THE SLIDE RULE IN THE COMPUTATION OF ROCK ANALYSES - - - James H. Hance 560 



LAKE SUPERIOR HIGHLANDS: THEIR ORIGIN AND AGE Charles Keyes 569 



SUMMARIES OF PRE-CAMBRIAN LITERATURE OF NORTH AMERICA FOR 1909, 1910, 1911, AND PART 



OF 1912 ..-.-..--------- Edward Steidtmann 57s 



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