50 proceedings: geological society 



THE GEOLOGICAL SOCIETY OF WASHINGTON 



The 260th meeting, the first meeting for the fall, was held in the 

 Cosmos Club, November 13, President Stanton in the chair. As an 

 informal communication F. C. Schrader gave a brief account of an 

 occurrence of bauxite in vertical fissure vein deposits thru limestone 

 in the Bovard district of southern Nevada. 



REGULAR PROGRAM 



The work of the Conservation Congress: David White. Mr. White. 

 was introduced as the new Chief Geologist of the Geological Survey, 

 this being the first public announcement of his appointment to succeed 

 Mr. Lindgren. He was received with hearty applause. , 



Reconnaissance in the Southern Wasatch Mountains: G. F. Loughlin. 

 The speaker presented certain structural and stratigraphic data col- 

 lected during a reconnaissance survey of the ore deposits in the Wasatch 

 Mountains from the Cottonwood district southward to the northern 

 ' part of the Mt. Nebo ridge. The only Pre-Cambrian exposure south 

 of the Cottonwood canyons is a band of Pre-Cambrian granite and 

 schists extending for a mile along the base of the Santaquin ridge. This 

 band is overlain unconformably by Cambrian quartzite about 800 feet 

 thick. The Cambrian quartzite was found to include the occurrences 

 mapped by the Fortieth Parallel Survey as the Ogden (Devonian) 

 quartzite. The "Ogden" quartzite in the Cottonwood district proved 

 to be a portion of the Cambrian, overthrust upon Madison (lower 

 Mississippian) and older limestone, ■ shale members in the overthrust 

 quartzite carrying Cambrian fossils. Blackwelder's elimination of the 

 Ogden quartzite in the northern Wasatch country is thus confirmed. 

 The "Ogden" quartzite in the Cottonwood, as well as in the American 

 Fork and Provo districts is overlain by the regular succession of Cam- 

 brian to Mississippian limestones — the same succession as is found above 

 the Cambrian quartzite on the Santaquin ridge; but the thickness of 

 the pre-Mississippian limestones is much less than in the Bear River 

 ridge to the north or in the Tintic range to the southwest. 



The stratigraphic section in the Cottonwood district is continuous 

 from the Pre-Cambrian thru the Triassic; but southward the Weber 

 (Pennsylvanian) have been bevelled off by an unconformity, since 

 Eocene (Wasatch?) conglomerate, east of the Santaquin ridge, rests 

 unconformably upon the upper Mississippian. West of Santaquin a 

 veneer of the Eocene conglomerate rests upon pre-Mississippian lime- 

 stone, and in the Sevier River Canj^on, the same conglomerate rests 

 upon Cambrian quartzite, thus showing that the whole Paleozoic section 

 was bevelled by the unconformity. At all these localities the Eocene 

 conglomerate is covered by patches of volcanic rocks, chiefly by a 

 coarse andesitic breccia. 



The principal structures noted are (1) westward overthrusts, including 

 that alreadv mentioned in the Cottonwood district and others at Santa- 



