1922] Vaughan: Geology of San Bernardino Mountains 411 



Contact minerals are found on the east corner of the triangular 

 area of limestone two miles south of the Rose Mine. Most of these 

 deposits occur as irregular patches of different sizes up to eight feet 

 long by four feet thick along the contact between the granite and 

 limestone. The latter overlies the granite and is somewhat broken up 

 and dips in all directions but at low angles near the largest contact 

 deposits. The minerals are garnet, quartz, a little biotite, and epidote, 

 the latter usually being the most prominent. A specimen examined 

 in thin section was found to contain about equal amounts of quartz, 

 epidote, and calcite with small granules of a uniaxial mineral having 

 a high refractive index and birefringence. This answers to the descrip- 

 tion of scheelite, and some of the crushed material was panned for 

 further examination. A white concentrate was obtained which turned 

 canary yellow upon the addition of hydrochloric acid. It turned blue 

 when boiled with tin, thus verifying the conclusion from the optical 

 tests that the mineral is scheelite. This paragenesis is of particular 

 interest in that it is unique, no other of similar nature having been 

 reported heretofore. 



The deposits are usually right at the contact and quartz is most 

 strongly developed on the granite side, but in one place the deposit 

 was wholly within the granite and the quartz was found on both sides. 

 Several small pegmatite dikes cut the granite, and it seems that where 

 these come in contact with the limestone the scheelite is most abundant. 

 It was noticed that in some cases the pegmatite extends a short dis- 

 tance into the limestone and along these dikes the contact minerals 

 are found even when the pegmatite is hardly more than a stringer. 

 No tremolite was found actually in these deposits, but in fissures in 

 the limestone near by. 



There is a small mine on the north side of the small hill east of 

 Rattlesnake Canon where it turns north. It has been driven into 

 the schists and follows small stringers of quartz containing free gold. 



