482 sMiTHSoMAx misce[.lanl;ous colli;CTioxs vol. 52 



to the cleavage, though many of the lines have apparently no definite 

 orientation. 



Qualitative chemical tests of the galena disclose, in addition to the 

 lead and sulphur, the presence of silver and antimony. A careful 

 examination for bismuth gave negative results. This becomes of 

 interest in view of the fact that in much of the galena from other 

 localities, known to possess octahedral cleavage, amounts of BiovS..;, 

 ranging around i per cent, have been found, and it has been sug- 

 gested that the peculiarity of cleavage might be due to the presence 

 of this impurity.* 



So far as the writer has been able to learn from a survey of the 

 most important literature on the subject, the peculiar development 

 of galena herein described has not been previously met with. 

 Scharff,^ Sadebeck,'' vom Rath," Hobbs,^ Franke,^ Miers," Rogers,^"^ 

 Miigge,^- Wada,^' and others have described galena bearing some 

 analogies to that here depicted, but in no case is the resemblance 

 more than partial. 



Tlic clialcopyritc. — This mineral occurs in an irregular mass 7 

 mm. in diameter, shown in plate Lix, figure i, and in two or three 

 other smaller aggregates. It presents no peculiarities, either of crys- 

 tal form or orientation. 



Genesis. — The following features may have some bearing on the 

 manner in which the specimen was formed : a few gold crystals are 

 imbedded in the galena and one is partly enclosed by chalcopyrite ; 

 one small mass of the chalcopyrite is set in the galena ; part of the 



* Dana's System of Mineralogy, 6th ed., p. 49. 

 " Previously cited. 



" Sadebeck, A. Ueber die Krystallisation des Bleiglanzes. Zeitsch. fiir. 

 Deutsch. geol. Gesel., vol. 26, 1874, pp. 617-670. 



' vom Rath, A. Mineralogische Notizen. See Zeitsch. fiir. Kryst., vol. 4, 1S80. 

 P- 425- 



* Previously cited. 



' Franke, H. Galenite und Dolomite von Oradna in Siebenbiirgen. Abhand. 

 d. naturw. Ges. Isis., 1896, p. 25. Abstract : Zeitsch. fiir Kryst., vol. 30, 1898, 

 p. 663. 



'" Miers, H. A. Mineralogische Notizen. Zeitscli. fiir Kryst., vol. 31, 1899, p. 

 584. 



" Rogers, A. F. Minerals from the Joplin Zinc and Lead District. Kan. 

 Univ. Quart., vol. 9, 1900, pp. 161-165. 



'" Miigge, O. Ueber rcgelmassige verwachsungen von Bleiglanz mit Eisenkies 

 und Kupferkies mit Kobaltglanz. Tschermak's min. u. petrog. !Mitth., vol. 20, 

 T901, pp. 349-354- 



" Wada. T. Mincralien Japans, 1904. .Abstract, Zeitsch. fiir. Kryst., vol. 43, 

 1907, p. 109. 



