328 



BULLETIN 131, UNITED STATES NATIONAL MUSEUM 



The crystal illustrated in Figure 96, also measured with the elon- 

 gation vertical, gave the angles recorded in the following table: 



Measurements of epidote crystal, Figure 96, elongation (h) vertical 



BLAINE COUNTY 



A specimen of massive dark green epidote from Blaine County 

 has been sent to the National Museum for identification by B. Z. 

 Smith, of Mountainhome, Idaho. 



CLEARWATER COUNTY 



Portions of deep green well-formed crystals of epidote up to 3 cm. 

 in diameter are present in considerable number in a coarse concen- 

 trate from placer gravels in Clearwater County associated with 

 rutile, corundum, tourmaline, garnet, etc. 



CUSTER COUNTY 



Epidote is very rare in the contact-metamorphic copper deposits 

 of the Alder Creek (Mackay) district as contrasted with its abundant 

 occurrence in the deposits of similar genesis in the Seven Devils 

 district. 



Specimens from the Basin prospect on the mountain across Park 

 Creek from the point where the Ketchum-Mackay road crosses the 

 Trail Creek divide, contain epidote associated with garnet, heden- 

 bergite, vesuvianite, wollastonite, prehnite, galena, etc. The epidote 

 occurs especially as the lining of small open spaces which were later 

 filled with prehnite. The epidote seems to be the latest of the sili- 

 cate minerals except the prehnite, but some perfect doubly termin- 

 ated crystals of epidote are completely surrounded by prehnite. 

 The crystals are all of simple lath shape elongated on the b axis and 

 flattened parallel to (T01). The orthodome zone contains broad 

 faces of (T01) with narrower faces of (T05), (103), (101), (301) and, 



