64 FLUORSPAR DEPOSITS OF SOT'THERN ILLINOIS. rBur.i.. 235. 



widely distributed, princii:)ally in metamorphic rocks. In the United 

 States it occurs from Maine to Virginia in the Piedmont and Appa- 

 lachian areas." In the Western States it is not uncommonly found in 

 small quantities in connection with metalliferous veins. In the JNIiss- 

 issijDpi Valley it is exceedingly rare. At one or two localities in cen- 

 tral Kentucky and Tennessee it occurs in nonmagnesian limestones. 

 From Tennessee it is now being shipped. It is reported to occur in 

 druses in the St. Louis limestone at St. Louis, and Mr. Ulrich has 

 observed a few crystals in the Ste. Genevieve limestone at the type 

 locality for that formation. With these exceptions it is not known 

 to occur at any point in the valley, and it is entirely absent from 

 all the lead and zinc deposits of the region, except those of this 

 j^articular district and the small deposits in central Kentucky near 

 Lexington. 



Abroad the most important localities for the production of fluor- 

 spav are the north of England and certain Saxon mining localities 

 in Germany. The English deposits occur in limestones of about 

 the same age as those of southern Illinois, and in many particulars 

 the occurrences are similar. This extends even to a close similarity 

 in the dike rocks present in both districts. In Saxony the fluorspar 

 occurs near Freiberg in veins and druses in gneisses, schists, and 

 slates, cut by dikes of quartz-porphyry and by gabbro. It is asso- 

 ciated with argentiferous galen.a, blende, stibnite, and many complex 

 com[)ounds not found in the Kentucky-Illinois district.'' 



Fluorine itself has been found in sea water, in boiler incrustations 

 of ocean vessels,' and Dana found it in calcareous corals. It occurs 

 in the bones of marine animals, and was found in small quantities 

 in the manganese nodules brought up by the ChaUenger nets from a 

 depth of 2,;^75 fathoms.'' 



From these notes it appears that fluorite may well be expected to 

 occur in small quantity in limestones and other sedimentary rocks, 

 but that its j^resence in unaltered limestones is very rare, and that 

 the only important bodies of fluorite known and worked commer- 

 cially are in limestones which have been intruded with igneous rock. 

 Both Mr. Emmons and ]\Ir. Tangier Smith have shown that the 

 apparently unaltered limestones of this district contain small quan- 

 tities of fluorine. 



« Dana, Mineralology, 6th ed., 1892, p. 163. 



"Von Cotta, B., Treatise on Ore Deposits (Prime translation). 1870, p. 98. 

 '■ Pnmpelly, Rapliael. Geol. Survey Kentucky, 2d ser., vol. 2, pt. 8, p. 46. 

 "* Deep-sea deposits, Report Challenger Expedition, p. 421. 



