598 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 58. 



a little fine-grained galena. A sample selected carefully, in order 

 to avoid galena, upon analysis afforded the following results: 



Analysis of houlangcrite from Przibram, Bohemia. 



Per cent. 

 Lead 55.08 



Antimony 24.38 



Iron Trace. 



Sulphur 18. 65 



Insoluble 1.10 



Total 99.21 



BISMUTOPLAGIONITE FROM WICKES, MONTANA. 



The name bismutoplagionite was recently given by the present 

 writer to a new lead sulphobismuthite received by the United States 

 National Museum from Mr. Tim McCarthy, of Wickes, Montana.^ 

 The specimens of ore in which the new mineral occurs came in 

 through the routine channels, with the request that the minerals be 

 identified and that the material be tested for platinum. Blowpipe 

 tests made by Mr. W. F. Foshag, of the Division of Mineralogy, 

 indicated that the gray constituent which was present in small 

 amount in a few of the pieces consisted essentially of a sulphide 

 of bismuth and lead. Further correspondence with the sender re- 

 sulted in the obtaining of a few additional small pieces of the ore, 

 some of which contained the gray bismuth-bearing mineral. 



OCCUBBENCB. 



Nothing was learned about the locality from which the specimens 

 were obtained, but it is presumed that they came from some unde- 

 veloped prospect in the vicinity of Wickes, which is a small min- 

 ing town in Jefferson County, north of Boulder. The specimens 

 as received consist of chunks an inch or two in diameter, consist- 

 ing mainly of coarsely crystalline pyrite, showing cubic crystals 

 with the corners truncated by octahedral planes. These masses of 

 pyrite contain, in addition to the bismuth mineral, nests of yellow- 

 ish scaly sericite, masses and prismatic crystals of quartz, and small 

 aggregates of chalcopyrite, tetrahedrite, and galena. The minerals 

 other than the bismutoplagionite occur in connection with the masses 

 of quartz. The bismuth mineral occurs rarely with the galena and 

 tetrahedrite, but for the most part it occurs interstitially with regard 

 to the pyrite crystals and in masses of the latter mineral which are 

 free from the other metallic minerals. Such pieces, when polished 

 and examined microscopically, show no lack of homogeneity in the 

 gray mineral. Only specimens which were unquestionably free from 



» Shannon, E. V., Amer. Joum. Sci., vol. 49, pp. 166-188, 1920. 



