OCT. 19, 1921 proceedings: geologicaIv society 423 



346th meeting 



The 34Gth meeting was held at the Cosmos Club at 8 p.m., on Wednesday- 

 April 14, 1920. 



Info rm al Communica tion 

 Dr. G. R. Mansfield showed some enlarged photographs of grains of 

 glauconite from the glauconite-bearing deposits of New Jersey, showing 

 the characteristic forms and microstructure of the grains. 



Regular Program 

 J. S. Brown: Fault features of the Salton Basin, California. (Illustrated.) 

 Salton Basin is in the southeastern corner of California. Its lowest point, 

 now covered by Salton Sea, is 273.5 feet below sea level. The basin is flanked 

 by mountain ranges on the southwest and northeast, but at the southeast 

 it opens toward the Gulf of California, from which it is separated by the delta 

 of Colorado River which is only 50 feet above sea level. The basin floor is 

 a desert plain covered at some places by large sand dunes. At many places 

 the basin is bordered by badlands. The stratigi'aphy consists essentially of 

 three groups: 



(1) Pre-Tertiary crystalline rocks, chiefly Paleozoic and Mesozoic, which 

 underlie the basin and compose the surrounding mountains. 



(2) Soft, saliferous sandstone and clay beds of late Tertiary age, usually 

 folded, exposed in the badlands. 



(3) Quaternary alluvium, generally undisturbed, forming the basin floor. 

 Salton Basin is generally conceded to be a graben. Numerous faults have 



been traced to its borders, the most notable being the San Andreas rift, 

 which extends to the northwestern tip of the basin. Topographic and geo- 

 logic evidence adduced by the writer indicates the existence of a fault 50 miles 

 long between the Tertiary of the badlands and thepre-Tertiary crystalline rocks 

 northeast of Salton Basin. The name Indio fault is suggested. The Indio 

 fault probably is a continuation of the San Andreas rift. Southwest of Sal- 

 ton Basin two systems of faults are distinguished whose intersections are re- 

 lated to the mountain spurs that project into the basin. These faults have dis- 

 turbed the pre-existing drainage and created a number of isolated mountain- 

 walled valleys. All the faulting observed is of the normal type. The fault- 

 ing that shaped the basin began before late Tertiary time, but has progressed 

 more or less continuously to the present day, as evidenced by movement 

 along certain faults in recent earthquakes. 



A. E. Fath: Origin of the faults, anticlines, and buried ''Granite Ridge'' 

 of the northern part of the Mid-Continent oil and gas field. (Illustrated.) 



J. B. Mertie, Jr.: The Salt Chuck palladium mine near Kasaan, Alaska. 



347th meeting 



The 347th meeting was held at the Cosmos Club at 8 p.m., on Wednesday, 

 April 28, 1920. 



Regular Program. 



David G. Thompson: Pleistocene lakes along Mohave River, California. 

 . Mohave River is a typical desert river. It rises in the San Bernardino 

 Mountains in southern California, and flows north to Barstow, thence 

 northeastward along the Los Angeles and Salt Lake Railroad. Except in 

 the mountains its channel is dry for many months at a time. Near the sta- 

 tion of Baxter the river emerges from a canyon and spreads over a large 

 alluvial fan, distributar}^ channels carrying the flood water to playas in two 

 separate closed basins, where it disappears by evaporation and absorption. 



