ORIGIN OF THE ORES. 
219 
Fluorite was first proved to exist in the spring deposits at Carlsbad by Berze¬ 
lius.® From bis experiments it is clear that waters may contain Si0 2 and CaF 2 , 
and that the two may be deposited together. Either of the two substances may 
be first deposited, and waters containing Si0 2 may subsequently dissolve the 
fluorite formed and replace it by quartz. According to Berzelius, the fluorite was 
dissolved as such in the waters of Carlsbad, which he says do not contain any sodium 
fluoride. The experiments of Bischof and Sorby would, however, show that the 
fluorine was present as sodium fluoride, for calcium fluoride and alkaline carbonates 
can not exist together in the same solution, and the Carlsbad waters contain a con¬ 
siderable amount of the latter salts. In mineral waters alkaline fluorides can, how¬ 
ever, exist together with calcium bicarbonate, as the two substances do not react. 
The testimony is somewhat conflicting, but it seems most likely that the waters of 
Cripple Creek contained sodium fluoride, and that the fluorite was separated by 
reaction of calcium silicate on the solutions. 
In tracing the origin of the fluorine we are first confronted by the fact that the 
Pikes Peak granite contains a certain small percentage of fluorite as a primary 
mineral/' in some cases, as in the Summit type, amounting to 0.55 per cent. In 
the vicinity of Cripple Creek no primary fluorite could be detected in the rock. 
However, if the fluorine were derived from the granite, we should expect secondary 
fluorite to be most common in this rock, which is certainly not the case in the dis¬ 
trict. Two or three miles south of Cripple Creek this granite does contain several 
small veins in which fluorite is associated with barite. The mineral is here either 
purple or green, the latter color never appearing in the deposits at Cripple Creek. 
It is very doubtful whether these veinlets really belong to the same class of deposits 
as those within the district proper. 
Another possibility is that the fluorine is leached from the volcanic rocks. No 
primary fluorite has, however, been observed in these and no definite traces of 
fluorine have been shown by the analyses. The presence of the mineral lovenite, 
if substantiated, would establish the presence of fluorine, but there seems to be some 
doubt regarding the identification (p. 65). As a third possibility, the fluorine, 
together with other volatile constituents, may have been given off by the phono- 
litic magmas on their consolidation at higher levels of the earth’s crust. We incline 
toward this view as the most probable explanation. There certainly exists a 
remarkable connection between phonolitic rocks and deposits containing fluorite 
and gold, exemplified not only at Cripple Creek, but also in the Black Hills, Judith 
Mountains, and Little Kocky Mountains/' 
CHLORIDES. 
The general distribution of sodalite in the Cripple Creek rocks indicates the 
presence of NaCl, and, in fact, the analyses of phonolites, latite-phonolites, and 
syenites show amounts of Cl up to 0.55 per cent. During the decomposition of this 
mineral by alkaline waters NaCl would be dissolved, and in this reaction is one 
aChemisehe Geoiogie, vol. 2, 2d ed., Bonn, 1864, p. 89. 
b Mathews, E. B., The granitic rocks of the Pikes Peak quadrangle: Jour. Geol., vol. 8, No. 3, April-May 1900, p. 237. 
cLindgren, W., Metasomatic processes in fissure veins: Trans. Am. Inst. Min. Eng., vol. 30, 1901, p. 657. 
