528 PROCEEDINGS OF THE ROCHESTER MEETING 



PHYSIOGRAPHY OF THE NORTHERN ROCKY MOUNTAINS 

 BY BAILEY WILLIS 



The two papers were discussed by A. P. Coleman, C. D. Walcott, and 

 the author. 



The fourth and last paper of the morning session was 



WALLS OF THE COLORADO CANYON 

 BY W. M. DAVIS 



[Abstract] 



The general profile of the canyon walls depends on rock structure, and not on a 

 pause in the elevation of the plateaus. The variation of profile from the narrow 

 canyon in the Uinkaret plateau to the wide canyon in the eastern Kaibab is due 

 to variation in the character of the strata. The pattern of spurs and recesses 

 varies with stage of dissection. The pattern commonly seen in the Red-wall cliffs 

 is repeated in the Tonto cliffs where the latter are much worn. The pattern 

 usually seen in the Tonto is repeated in the Red-wall where it is less worn. Brief 

 mention is made of details connected with the unconformities seen in the canyon 

 walls. 



Remarks were made by the President. 



The Society adjourned for the noon recess and reconvened at 2.30 p m, 

 when the following paper was read : 



ROCK BASINS OF HELEN MINE, MICHIPICOTON, CANADA 

 BY A. P. COLEMAN 



The paper is printed as pages 293-304 of this volume. 

 The second paper was 



EFFECT OF SHORELINE ON WAVES 

 BY W. M. DAVIS 



[Abstract] 



The paper described the transformations of waves as they run in on shorelines 

 of different forms, with special reference to the refraction of waves on headlands 

 and in bays, and to the formation of surf. 



The third paper was 



VARIATION OF GEOTHERMAL GRADIENT IN MICHIGAN 

 BY ALFRED C LANE 



[Abstract] 

 The rate of increase of temperature observed in deep mines and borings has 



