Ubc S^ournal of (3eologi? 



Vol. XXIII CONTENTS FOR MAY-JUNE J9J5 No. 4 



THE EVOLUTION OF HERBACEOUS PLANTS AND ITS BEARING ON CERTAIN PROBLEMS OF GEOLOGY 



AND CLIMATOLOGY Edmund W. Sinnott and Irving W. Baiiey 289 



POST-CRETACEOUS HISTORY OF THE MOUNTAINS OF CENTRAL WESTERN WYOMING. PART III 



Eliot Blackwelder 307 



THE GEOLOGY OF CENTRAL MINAS GERAES, BRAZIL. PART I - E. C. Harder and R. T. Chamberlin 341 



REVIEWS . - 379 



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