Vol. 6] Baker: Cenosoic History of the Mohave Desert, 337 



alternate white and gray bands. The slates are micaceous, prob- 

 ably muscovitic, with very good cleavage into thin plates of 

 large dimension, and probably form thin bands or lenses in the 

 marble. The metamorphic series is tilted and faulted, and 

 intruded by granitic rock with apophyses of orthoclase-muscovite 

 pegmatite containing small dark-red garnets. Save the garnet, 

 which was noted only in the pagmatite, no characteristic contact- 

 metamorphic minerals were found. The series has been corre- 

 lated by Hershey on purely lithologic grounds with the Lower 

 Cambrian strata of Inyo County, California. 



BASEMENT EOCKS OF THE SAN BERNARDINO RANGE 



A large body of altered limestone, in which characteristic 

 contact-metamorphic minerals have been developed, has been 

 intruded by granitic rock in Furnace Canon, in the northwest 

 corner of the San Gorgonio Atlas Sheet. Two masses of the 

 intrusive are connected by a dike varying from several hundred 

 down to one hundred feet in width, which is more finely crystal- 

 line at its borders than in the middle, and can be easily traced 

 across the slopes by its light brown weathered outcrop. Masses 

 of tremolite, with fibers varjung in size from several inches in 

 length down to minute needles, are extensively developed in the 

 limestone hundreds of feet from the intrusive contact. This 

 mineral is especially abundant in the vicinity of the Wild Rose 

 mine, in Wild Rose Canon, a tributary of Furnace Canon, where 

 it makes up the greater part of the rock. The minerals cyanite, 

 epidote, chlorite, clialcopyrite, and specularite were noted close 

 to the intrusive contact. Copper was found in very small lenses 

 containing the original mineral clialcopyrite, in places second- 

 arily enriched to chalcocite, with azurite and chrysocolla, min- 

 erals of the zone of surface oxidation. Another body of contact- 

 metamorphosed limestone was noted in Upper Holcomb Valley. 



Other metamorphic rocks of the San Bernardino Range com- 

 prise argillaceous limestone with imperfect slaty cleavage, schists, 

 and gneisses. The intrusive rocks found probably all belong- 

 to the family of granites, varying in texture from rather fine- 

 grained dike rocks to very coarse-grained plutonics. A very 

 coarse porphyry, with flesh-colored orthoclase phenocrysts as 



