BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 26, pp. 389-408 November 22, 1916 



PROCEEDINGS OF THE SUMMER MEETING OF THE GEO- 

 LOGICAL SOCIETY OF AMERICA, HELD AT THE UNI- 

 VERSITY OF CALIFORNIA AND AT STANFORD UNIVER- 

 SITY, AUGUST 3, 4, AND 5, 1915.i- 



J. A. Taff, Secretary 'pro tern. 



CONTP^NTS 



Page 



Session of Tuesday, August 3 .390 



Titles and abstracts of papers presented and discussions thereon.... 391 

 Epigene profiles of the desert [abstract and discussion] : by 



Andrew C. r^awson 391 



Bajadas of the Santa Catalina Mountains, Arizona [abstract and 



discussion] ; by C. F. Tolman, Jr 391 



Origin of the tufas of Lake Lahontan [abstract] ; by J. C. Jones. . 392 

 Some physiographic features of bolsons [discussion] ; by Herbert 



E. Gregory 392 



Sculpturing of rock by wind in the Colorado Plateau province; 



l)y Herbert E. Gregory 393 



Session of Wednesday, August 4 .393 



Titles and abstracts of papei-s presented and discussions thereon .393 



Some chemical factors affecting secondary sulphide ore enrich- 

 ment [abstract and discussion] ; by S. W. Young 393 



Itole of colloidal migration in ore deposits [abstract and discus- 

 sion] ; by John D. Clark 394 



Examples of progressive change in the mineral composition of 



copper ores [al)stract and discussion] ; by C. F. Tolman, .Tr. . . . 394 

 Sericite, a low temperature hydrothermal mineral [abstract] ; by 



A. F. Rogers 395 



Dinner 39.^) 



Session of Thursday. August 5 .39,5 



Titles and abstracts of pajiers presented and discussions thereon 39.5 



Physiographic control in the Philippines [abstract and discus- 

 sion] : by Warren D. Smith 395 



Origin of the basins within the hamada of the Libyan Desert 



I abst ract] ; by William IT. Hobbs .396 



Limited effective vertical range of the desert sand-blast, based 

 on observations made in the Libyan Desert and in the Anglo- 



Egyi)tiaii Smlan | iihstract] ; by William H. Hobbs .396 



('liaractcristics of tlic Lassen Peak eruptions of May 20-22. 19ir> 

 [abstra<-t mimI .lisciission | : by Kuliff S. Holway and J. S. Diller. 397 



* Manuscript rpcoivcd 1)\ the Sccrt'tjirv ni' tin- Society Oct.ilwr 1.'^. 101.". 



XXXI — Boll. Geol. Soc. Am., Voi,. 26, 1014 ^389) 



