THE MINERALS OF IDAHO 



217 



observed in garnet rock that is clearly of porphyry derivation. 27 In 

 the Bay Horse district calcite crystals have been noted lining cavities 

 in the oxidized lead ore of the lead-silver deposits. In the Yankee 

 Fork district calcite as a gangue mineral in the silver ores in asso- 

 ciated with some quartz, chalcedony and opal, and is in the form of 

 irregular areas and also as lamellar crystals of the variety described 

 below as argentine. It is often largely replaced by quartz. 28 



ELMORE COUNTY 



Specimens from 5 miles below Glenns Ferry in Elmore County 

 collected by C. F. Bowen in 1911 consist of vesicular basalt, the 

 cavities of which are lined with amber crystals of calcite up to 5 mm. 

 in diameter overlain by two white zeolites, probably chabazite and 

 thomsonite. The calcites are relatively simple in habit and develop- 

 ment, as shown in the drawing, Figure 43, and the forms present are 

 only the two rhombohedrons 2>(H21) and <j?(2241). These gave the 

 following angles: 



Measurement of calcite, Figure 43, Elmore County 



Calcite occurs at a number of places in Lemhi County. A speci- 

 men from the Pittsburg-Idaho mine, Texas district, has been illus- 

 trated by Umpleby. 29 A crystal from this specimen was measured 

 and is illustrated by the drawing, Figure 44. The forms and angles 

 are as follows : 



Measurement of calcite, Figure 44, Lemhi County 



« J. B. Umpleby. U. S. Oeol. Survey Prof. Paper 97, p. 50, 1917. 



» J. B. Umpleby. U. S. Geol. Survey, Bull. 539, p. 85, 1913. 



» J. B. Umpleby. U. S. Oeol. Survey, Bull. 528, pi. 10, p. 64, 1913. 



54347— 26 1 15 



