TITLES OF PAPERS 179 



In response to an inquiry, Professor Tolman defines the bajada as 

 coalescing fans that let down from the mountain base to the bolson. 

 Bajada should apply only to surface forms and not to other dimensions. 



Discussed by Professor Lawson, who compared the bajada material to 

 fanglomerate. 



ORIGIN OF THE TUFAS OF LAKE LAHONTAN 

 BY J. C. JONES 



Presented extemporaneously. 



Discussion was deferred. 



The session adjourned at 12.10 p. m. for luncheon. 



Seventy-five members and visitors were present. 



A short business session was held to consider the election of officers of 

 tlie Cordilleran Section for the ensuing- year. 



Moved by Dr. Lawson and voted, that the Secretary call for a nomi- 

 nating ballot, through correspondence, for election of officers at a meeting 

 to be called for the purpose. 



The Section adjourned to convene in the afternoon, following a meet- 

 ing of the Paleontologic Section. 



The afternoon session was called to order by Vice-President E. 0. 

 Ulrich, of the Geological Society, at 4.20 p. m., when the following papers 

 were read and discussed : 



SOME PHYSIOGRAPHIC FEATURES OF BOLSONS 

 BY H. E. GREGORY 



SCULPTURING OF ROCK BY WINDS IN THE COLORADO PLATEAU PROVINCE 



BY H. E. GREGORY 



Pead in full from manuscript by C. F. Tolman, Jr. 



Discussion 



C. F. Tolman, Jr., named types of protected surfaces in desert regions: (1) 

 Vegetation; (2) Coarse gravel and boulders, making pavement; (3) Caleche 

 and surface soil cements; (4) Desert pavements, angular gravel, forming 

 mosaic; and (5) Clay in bottoms of playas. 



Horace B. Patton stated that wind is abrading rather than transporting, 

 and cited deep holes that have been formed by wind. 



E, E. Free referred to salt cements in deserts as protection against wind 

 erosion. 



Erasmus Haworth and J. C. Ray discussed protecting effects of alternating 

 coarse and fine, hard and soft, strata. 



J. C. Jones discussed deposition by winds. 



