344 Turner — Unusual Minerals from the Pacific States. 



The gneiss is composed chiefly of plagioclase, amphibole, 

 pyroxene, reddish brown biotite, quartz, with accessory pyrrho- 

 tite, titanite, magnetite, zircon and apatite. 



The heavy minerals were separated from the other constit- 

 uents by means of the Thoulet solution. The magnetite was 

 extracted with a horse-shoe magnet, and the amphibole, pyrox- 

 ene and biotite with an electro-magnet. The remaining powder 

 contained titanite, zircon and apatite. This was examined 

 chemically by Dr. "W". F. Hillebrand, who states that " the 

 apatite contains a very small amount of chlorine, but appar- 

 ently no fluorine whatsoever; at least it could not be detected. 

 Neither does there seem to be hydroxy 1 replacing fluorine or 

 chlorine." It thus appears in this instance that the apatite is 

 neither a fluor- or a chlor-apatite. 



Vivianite (Fe 3 P 2 8 + 8H 2 0).— Prof. H. G. Hanks* reports 

 this mineral from the Bree ranch in Los Angeles Co. asso- 

 ciated with asphalt. The vivianite is in small enclosed nodules, 

 never larger than a pea and generally smaller. 



Silicates. 



Chloropal. — In the Palmetto Mountains and in the southern 

 part of the Silver Peak Pange in Esmeralda County, Nevada, 

 there are numerous dikes and interbedded layers of light 

 colored acid lavas (meta-rhyolites and meta-dacites) in cherts of 

 Ordovician age. These cherts, or rather layers of thin slate in 

 them, contain the remains of graptolites. In one of these 

 streaks of acid lava at a point about fifteen miles SW. of 

 Silver Peak village, there was found a vein of yellowish-green 

 material having the following composition. 



Analysis of yellow-green material. 



By George Steiger. 



Per cent. 

 Insoluble less Si0 2 soluble in Na 2 C0 3 after treat- 

 ment with HC1 51-5 



Si0 2 soluble after treatment with HC1 . . 19* 



Fe 2 3 soluble in HC1 _ , 13-5 



CaO « " 3-4 



MgO " " 0-5 



Alkalis none 



H 2 calculated by difference 9-5 



CO„ " from CaO 2-6 



100-0 



Leaving out the impurities, CaO, C0 2 , and insoluble material 

 and calculating to 100 per cent, we have : 



* 4th Ann. Rep. State Mineralogist of California. 



