RUBY COmiNDUM FROM (JALIFORNIA 798 



RUBY CORUNDUM FROM SAN BERNARDINO COUNTY, CALIFORNIA 

 BY GEORGE D. LOUDERBACK AND W. C. BLASDALE 



{Ahstract) 



A hitherto undescribed locality recently called to the writer's attention 

 shows the occurrence of corundum as an igneous secretion followed by a his- 

 tory of partial metamorphism, impregnation, brecciation, and weathering of 

 the inclosing rocks. The mineral is in part automorphic, with very simple 

 forms. The rock and its associations are described and analyses presented. 



The paper was illustrated by specimens. 



SOME TOPOaRAPHICAL FEATURES OF THE WESTERN SIDE OF THE COLORADO 



DESERT 



BY H. W. FAIRBANKS 



{Abstract) 



The San Jacinto Mountains send out a long spur southeastwardly into the 

 western part of the Colorado Desert. This spur is known as the Santa Rosa 

 Mountain. The accumulations of the desert appear to have been built up 

 against the foot of this range as though it had undergone subsidence. 



An arm of the Colorado Desert reaches in behind the Santa Rosa Mountain, 

 and this is known as the Borego Desert. At the western end of this desert, 

 close under the steep scarp of the Peninsula range, there is an alkali sink evi- 

 dently due to subsidence of the desert. 



At the end of the Santa Rosa Mountain, where the Borego Desert opens out 

 into the main Colorado Desert, there are extensive beds of late Tertiary age. 

 These have been folded slightly, and subsequently planed off. Then an uplift 

 took place and another partial planation occurred. Finally the beds were 

 dissected, and at their lower exposed margin eaten into by the waves of the 

 ancient Salton Sea. 



SERPENTINES OF THE CENTRAL COAST RANGES OF CALIFORNIA 

 BY H. E. KBAMM" 



(Ahstract) 



The paper presented a brief history of the work done on the California ser- 

 pentines. In particular it was a mineralogical and petrological description of 

 serpentines and associated minerals in the central coast ranges of the State. 

 The derivation of the serpentines from eruptive rocks was shown. 



The following papers were read by title : 



A NEW EROSION CYCLE IN THE GRAND CANYON DISTRICT, ARIZONA 

 BY H. H. ROBINSON 



• Introduced by J. C. Branner. 



