168 PROCEEDINGS OF THE AMERICAN ACADEMY. 



bluish green color due to included fibers of the blue crocidolite. The 

 hollow casts left by the solution of such crystals have already been 

 described. 



In one or two cavities in the Fallon pegmatite there were seen tiny 

 cubes of fluorite implanted on quartz, and in another such pocket, 

 peculiar in containing also crystals of calcite, the cube was modified 

 by two hexoctahedrons which appear to be new to fluorite. The 

 measurements and derived symbols of these forms follow : 



Calculated. Measured. Limits. Readines. 



4> P 'P P </> P 



( 3.10.16 m°A2' 33°07' 15°45' 33''20' 



< 3.16.10 10 38 58 26 10 36 58 33 10°30'- 10°42' 58°30'- 58°36' 2 

 (10.16.3 32 00 80 58 32 04 81 05 31 52 - 32 16 80 50 - 81 20 4 



( 259 21 48 30 54 21 01 31 15 20 45 - 21 18 31 11 - 31 19 2 



< 295 12 32 61 32 12 32 61 25 12 27 - 12 37 61 23 - 61 26 2 

 ( 592 29 03 79 00 



Calcite. — Certain small pockets in the Fallon pegmatite were filled 

 by a final deposit of calcite. In one or two cases the calcite supplied 

 was insufficient to wholly fill the open space and in these cavities 

 calcite crystals were found showing the somewhat unusual combination 

 of prism and base only, m(lOTO) and c(OOOl). 



Wulfenite. — Thin coatings of light yellow color as well as tiny 

 crystals of Wulfenite were found on smoky quartz in the crocidolite 

 pocket. The crystals are in part model-perfect combinations of first- 

 order pyramid with third-order prism, n( 111) and f(320), see Figure 6, 

 p. 990, Dana, System, in part cube-like combinations of a prism and 

 the base. The amount of wulfenite is very small and its presence is 

 easily accounted for by the association in the same region of the 

 pegmatite of molybdenite and galena. 



