288 Cross and Hillebrand—Cryolite from Colorado. 
gled among each other in every sort of direction, which gives 
the mass an appearance of opacity much resembling that of 
kaolin or chalk.” 
Chemical analysis showed it to consist of 
Equivalents. 
Al 16°23 with F 33°64 = 49°87 0°59 
Ca 22°39 oS BRT oe. 48°66 }-12 
Na 0°43 ater ue C33 = O76 
94°29 
Water 5°71 0°63 
100°00 
The fluorine seems to have been calculated for the metals, and 
the water was found by difference. 
rom the above data the author obtains the formula 2CaF,, 
very fair agreement of his analytical data for the metals with 
those of Hagemann, and the similarity in occurrence, appear- 
ance and physical characteristics of the two minerals must have 
led to at least a suspicion of their identity. There can hardly 
exist a doubt that Flight has analyzed gearksutite, and that 
the name evigtokite is therefore to be dropped. 
PROSOPITE. : 
This rare species hitherto unobserved in association with 
the cryolite minerals, and known only in connection with: the 
tin-bearing veins of Altenberg, in Saxony, has been identified 
in both veins at St. Peter’s Dome. It is most abundant 1D 
vein B, and the chief description of it will come under that 
head, but close examination has proved its presence also among 
the minerals of vein A. . 
Both of the coarsely crystalline specimens of pachnolite, 
above described as A and B, have prosopite upon them. ‘5p! 
imen B is, in parts, in process of alteration to a dull, white, 
porous substance, with little cavities in which are minute crys 
tals of prosopite. These are colorless, transparent, tabular 1D 
shape, showing 7-4 (010) Lapsioripicee I (110), 1 (111) and —2-2 
an 
determined as prosopite in vein B. In two other specimens of 
surfaces when decomposition of the pachnolite has already 
* Probably a printer’s error. It should read 2CaFs, AlaFs, H.0. 
