CALIFORNIA ACADEMY OF SCIENCES. 365 



tory of the University of California, by Mr. Adolf Webber. 

 0.0212 gram, of the substance yielded 0.0198 gram, of carbonate 

 of lime, the difference consisting of water and boracic acid. One 

 has consequently a partial pseudomorph of calcite after coleman- 

 ite, instead of pandermite after colemanite, as I had surmised. 



Pyrite and Albile from Stanislaus Gold Mine, Calaveras County, 



California. 



During the latter part of October, 1835, I received from Supt. 

 Buckminster of the Melones Consolidated Mining Co., of San 

 Francisco, a few small specimens from the Stanislaus Gold Mine, 

 one of several mines in the Carson Hill Mining District, Calave- 

 ras County, California, operated by the Melones Co. The sharp 

 observation of Mr. Buckminster had detected a few very delicate, 

 metallic, speiss yellow needles, which he thought would be 

 worthy of a closer examination. 



With respect to the occurrence of the specimens, Mr. Buck- 

 minster writes, under date of December 13th, 1884, that they 

 were taken " from the Stanislaus mine, one of the numerous 

 " gold veins in the slate belt of the so-called ' Mother Lode ' of 

 " California, about 280 feet below the surface, a few more having 

 " been later discovered eighty feet vertically under the former. 

 " The specimens were taken from small lenticular secretions of 

 " silica in a local layer of black talc slate near the line of its 

 " contact with a continuous stratum of foliated talc, the slate and 

 " talc both containing numerous embedded cubes of the pyrite." 



The few small specimens in hand consist of small fragments of 

 hard, dark gray, slaty material, thickly impregnated with pyritic 

 granules and firmly cemented together by snowy white albite, in 

 the drusy cavities of which the needles occur. These latter are 

 long, delicate forms, the larger showing bright metallic luster 

 and speiss yellow color. They vary in thickness from 0.05 mm. 

 down to the size of the merest delicate hair-like form, and are 

 sometimes 10 or 12 mm. in length. The needles are singly im- 

 planted on the walls of the crystal cavities, projecting freely out 

 into the vacant central space. In one small cavity numerous 

 •extremely delicate, to the unaided eye barely visible, hair-like 



