Mr. L. Fletcher's Crystallographic Notes. 187 



from Oker : (1 3 1) (4 3 4) were observed on only two of 

 these crystals. 



The form (131) has since been observed by Zepharovich* 

 slightly developed on a crystal from near Miss in Carinthia. 



The forms (310), (2 3), (119), (4 3 4) have not been 

 met with on any crystals in this collection. 



Some crystals were removed from a specimen of unknown 

 locality : the colour of the crystals resembles very much that 

 of some specimens from the Lipari Isles, while the accompa- 

 nying rock is a highly altered scoriaceous lava. One crystal, 

 about 3 millimetres in diameter, presented the combination 



(100) (101) (110) (111) (112) (113) (311) 

 (313) (315), 



of which (311) is one of the rare forms due to Brezina : the 

 form (1 1 2) has been long known, but did not occur on 

 the crystals from Oker. Another fragment from the same spe- 

 cimen, and about 4 millimetres in diameter, was found to con- 

 sist of two interpenetrant crystals, one individual presenting 

 the combination 



(100) (010) (001) (011) (013) (101) (110) 

 (111) (113) (115) (117) (311) (313) (315), 



of which both of the forms (3 1 1), (1 1 7) are due to Brezina, 

 and in this crystal are largely developed ; the old form (0 1 1) 

 presented by this individual was not present on Brezina's 

 crystals. The second individual presented the combination 



(001) (103) (111) (311) (313) (315). 



Some small crystals from the Wheatley Mines, Phoenixville, 

 Chester Co., Pennsylvania, were found to be exceeding rich in 

 the development of planes, and likewise showed some of the 

 rare forms mentioned above. 



A crystal of about 1 millim. diameter, from a specimen in 

 which the sulphur was associated with anglesite, galena, and 

 copper pyrites, was found to present the following combina- 

 tion : — 



(011) (010) (110) (115) (113) (112) (111) 

 (101) (313) (117) (311). 



A second specimen from the same mine showed the associa- 

 tion of sulphur with cerussite and quartz; a crystal of about 

 1 millim. diameter presented the following forms, the magni- 



* Jahresberichte des Vereines " Lotos " in Prag, 1878. 



