XTbe journal of (3eoloc$£ 



Vol. XXIV CONTENTS FOR JANUARY-FEBRUARY \916 No. \ 



THE ACADIAN TRIASSIC. PART I Sidney Powers i 



AVERAGE REGIONAL SLOPE, A CRITERION FOR THE SUBDIVISION OF OLD EROSION SURFACES 



Leopold Reinecke 27 



CAIMANOIDEA VISHERI, A NEW CROCODILIAN FROM THE OLIGOCENE OF SOUTH DAKOTA 



Maurice G. Mehl 47 



ON THE STRUCTURE AND CLASSIFICATION OF THE STROMATOPOROIDEA - - - - M. Heinrich 57 



THE PHYSIOGRAPHY OF MEXICO Warren N. Thayer 61 



REVIEWS 95 



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