THE MINERALS OF IDAHO 



241 



who never refer to the crystals as carbonate. Although it is mani- 

 festly impossible to list all of the occurrences of so widely distributed 

 a mineral, a number of those which have been brought to my attention 

 are mentioned below. A number of crystals were measured and, 

 although they present no especial peculiarities, the measurements are 

 reproduced with figures of many of the crystals merely to record the 

 habits and developments of cerusite from the several localities, since 

 crystals from the State have 

 never before been described. 

 An exhaustive treatment of the 

 crystallography of the cerusite, 

 especially of the Coeur d'Alene 

 district, would doubtless de- 

 velop many facts of interest and 

 might profitably be undertaken 

 were the material available. In 

 the present work only poor 

 material has been at hand, 

 principally, the crystals being 

 accidentally included in ran- 

 dom ore samples. 



BEAR LAKE COUNTY 



In the St. Charles district in 

 the Bear River Range cerusite 

 of dark color surrounds crys- 

 talline aggregates of galena in 

 a gangue of iron-stained lime- 

 stone with some siderite. 62 



BLAINE COUNTY 



Cerusite is common in the 

 surface ores of almost every 

 district of this county. It was 

 formerly common in the Hailey 

 region as massive ore and occa- 

 sionally in groups of reticulated crystals. In the Era district 

 cerusite is associated in the oxidized ores with small amounts of smith- 

 sonite, cerargyrite, and proustite. 62a In the Birch Creek mine, Birch 

 Creek district, the cerusite, which has a peculiar grayish-black color 

 thought to be due to the manganese it contains, is associated with 

 smithsonite, galena, anglesite, and a little wulfenite. 63 



62 R. W. Richards. U. S. Oeol. Survey, Bull. 470, p. 1S2, 1911. 



«° J. B. Umpleby. U. S. Oeol. Survey, Prof. Paper 97, p. 121, 1917. 



43 Idem, p. 119. 



Fig. 52— Cerusite. Simple prismatic crystal elon- 

 gated ON THE AXIS. GOLDEN GLOW MINE, WARM 



Springs district, Blaine County 



