-Mineralogical Notes. 



45 





Average. 



Calculated. 



irements 



67° 25' 



67° 30' 



u 



67° 55' 



67° 30' 



calcite. g consists of smooth narrow faces truncating the polar 

 edges of «■ The faces of the latter are very rough, channeled 

 parallel to their intersection edge with g, and pitted. The 

 angle g /\ r (cleavage face) 0552 ^ 1011 was measured with 

 the following results, the contact goniometer being used. 



Crystal 1 



The form w was identified by the fact that the g face trun- 

 cates its polar edges, as measurements were not possible on 

 account of the rough surface. 



2. A New Form on Galena. 



Several crystals of galena associated with sphalerite and 

 calcite from an unknown locality are thought to be worthy of 

 brief mention here. The forms present are the tetragonal 



trisoctahedron *p (13*1 *1) and the octahedron o (111). The 

 crystals have a tetrahedral aspect due to the unequal develop- 

 ment of the octahedral faces (fig. 4). p (13-1-1) is a new form 

 for galena and is not mentioned as occurring on any isometric 

 mineral in the 6th edition of Dana's System. It is striated 

 parallel to its intersection edge with the octahedron, but good 

 measurements were obtained, as the following table shows. 



p 13-1-1 

 o 13-1-1 



13.1.1 

 1-1-1 



48' 



Limits. 



Average. 



Calc. 



44'- 8° 48' 



8° 46' 



8° 46' 



29-48° 32' 



48° 30' 



48° 3lV 



3. Pyrite Crystals from Weehawken, N. J. 



Occurring in the calcite veins of the trap near Weehawken, 

 N. J., are found small crystals of pyrite with the following 

 forms o (111), e (210), M (432), the latter as narrow faces trun- 

 cating the edge e/o. Figure 5 gives an idea of their habit. 

 The markings, equilateral triangles on o and isosceles triangles on 

 e, are almost identical with the etch figures, and like them indicate 



