346 



TAYLER ON THE CRYOLITE OF GREENLAND. 



of tinstone, and carbonate of iron. In one of these cavities is a 

 large vein of arsenical pyrites and purple fluor-spar ; also a lai-ge 

 vein of black cryolite, containing copper- and iron-pyrites, and 

 red felspar. Smaller cavities are found when blasting, the sides 

 of which are completely covered with crystals of the tantalite, 

 resembling on a large scale the crystalline cavities in amygdaloidal 

 traps.^ In this quartz and felspar rock there is a remarkable vein, 

 containing soft ferruginous clay and rolled pebbles, sparry-iron-ore, 

 and copper-pyi-ites. The copper lies over the sparry-iron, and 

 runs in fine threads between the folia of the partly decomposed 

 iron-ore, appearing as if it had run into it in a state of solution. 

 To this quartz and felspar rock succeeds more granitic gneiss, in 

 which the cryolite occurs ; this gneiss gradually loses its granitic 

 character as it approaches the eastern trap-vein, where it again 

 takes on the same slaty appearance as at the western trap- vein. 



Fig. 2. 



South. 



-Transverse Section of the Cryolite at Evigtok. 

 (The width of the Cryolite is about 80 feet.) 



North. 



g, g. Gneiss. 



i. Sparry-iron-ore. 

 q. Quartz vein. 

 /. Argentiferous galena. 

 /. Purple fluor-spar. 



Black Cryolite. 



pi, pi. Galena, coppcr.pyrites, blende, 

 iron-pyrites, and carbonate of iron, scat- 

 tered in cryolite. 



* A fragment of cryolite was found 

 imbedded at this spot. 



We will now refer to the transverse section of the cryolite 

 (fig. 2). The cryolite forms a bed or vein parallel to the strata, 

 and is about 80 feet thick and 300 feet long ; it dips to the south 

 at an angle of nearly 45°, and runs nearly E. and W. In the 

 upper wall of gneiss, about 2 feet above its junction with the 

 cryolite, runs a vein of sparry-iron, with the same dip as the 

 cryolite ; and a layer of opaque quartz crystals lines the under side 

 of the gneiss, between the iron-ore and the cryolite. Sometimes 

 sinking several feet into the cryolite, but never rising into the 

 gneiss, is a vein of argentiferous galena, containing 33J per cent, 

 of lead and 45 ounces of silver in the ton of ore ; this was worked 

 during the year 1854-5, and some good ore was extracted. The 

 cryolite below this vein is impregnated for a few feet with galena, 

 copper-pyrites, and sparry -iron-ore ; but beyond, until within a 



