jr. P. Blah — Mineralogical Notes. 45 



and one-eighth to one-quarter of an inch in thickness. The 

 prismatic planes /. /. are generally nearly obliterated, or are 

 absent, through the great development of the hemi octahe- 

 dral planes -1, replacing the obtuse terminal edges. The termi- 

 nal plane, <K is chiefly developed and this with the broad 

 planes replacing the obtuse edges gives to some of the crystals 

 the appearance of rhomhohedrons of the minus series. The 

 general habit of the crystals is similar to those from Wester- 

 In near Stassfrirt described by Zepharovich ;* with the pre- 

 dominating pyramid —1, occur also the pyramids — -J-, — \ and 

 either — £ or — 4 ; traces of a pyramid on the acute edges have 

 also been noted. There is evidence that the crystals vary great- 

 ly in size and in their habit in different parts of the deposits. 

 They occur also in the midst of portions of the solid thenard- 

 ite as inclusions, and in one instance a small crystal was found 

 in the midst of a transparent mass of halite. Close inspection 

 of the transparent tabular crystals from the green clay reveals 

 the presence of crystalline cavities with fluid inclusions made 

 evident by the movement of small bubbles. When heated the 

 decrepitation is violent. 



Carbonate of lime pseudomorphs. — Where the lower bed 

 containing the bulk of the glauberite crops out at the surface 

 and has become oxidized and dried, the glauberite disappears and 

 is replaced by carbonate of lime in an amorphous condition but 

 having the exact form of the glauberite crystals, whose matrix 

 they have filled. These pseudomorphs are firm, compact and 

 dense, but are without cleavage or interior crystalline structure. 

 Color, cream-yellow. They weather out in great numbers and 

 show that the glauberite must occur in a great variety of sizes 

 and forms of aggregation, in some places in rosettes and in 

 others in crystals two or three inches long. 



2. Bour)ionite in Arizona. 



Bournonite occurs sparingly at the Boggs Mine, Big Bug 

 District, Yavapai County, Arizona Territory, associated with 

 pyrite, zinc blende, galenite and copper pyrites. The crystals 

 are brilliant and characteristic, with interesting modifications 

 not yet studied and compared. This is believed to be the first 

 announcement of the occurrence of this species in the United 

 States. I am indebted tto Fred. E. Murray, Esq., superintend- 

 ent of the mine, for specimens. 



* Sitzungsber. Akad. YTieD, vol. Ixix, 1ST 4. 



