102 Minerals from Greenland. [Feb, 



panied by sparry iron ore unconnected with cryolite. These 

 were disposed on sienite; but although the aspect of this fossil 

 is exactly the same, it would be stretching analogy too far to 

 assert from this that sienite was the geognostic repository of 



.cryolite. 



This substance obtained a very high estimation in the mineral 

 market. I have in my possession a small specimen for which a 

 friend of mine paid four pounds ; and. taking its weight and price 

 as the ratio, the value of all the cryolite in this parcel would 

 have exceeded the sum of 5000/. 



apatite. 



This mineral I found in three different states : first in grains 

 pf a pale greenish yellow colour, mixed with lamellar hornblende 

 and magnetic iron ore; a combination which occurs in the iron 

 mines of Lapland and Norw'ay. The gecond is in transparent 

 colourless crystals, of an hexagonal form, with terminations set 

 at right angles to the axis, accompanied with dark brown mica 

 and augite, both crystallized : and also with calcareous spar, in 

 which the apatite was imbedded. In the third the apatite is of a 

 greenish colour, somewhat siniilarto the moroxite of Kongsberg, 

 and crystallized in short hexagonal prisms, imbedded, along with 

 crystals of felspar, in abase of brick-red compact felspar, forming 

 a species of porphyry hitherto unknown. There was only one 

 specimen of this curious rock in the collection. The only other 

 acidiferous minerals were carbonate of lime and fluor spar: of 

 the former I found only one crystallized piece, and one or two of 

 a fine white granular variety, similar to the marble of Carrara. 

 Of the fluor I noticed one small mass of a purple colour, and 

 some pa|e green pieces accompanying augite and felspar. 



Qiiarlz, 



This is too common a substance to make it necessary for me 

 to say much here : it however occurred in some unusual varieties. 

 The most conspicuous was of a very common kind, although to 

 appearance the specimens were more carefully chosen and pre^ 

 se^rved than any of the other minerals. The masses are of a flat 

 shape, formed of a congeries of crystals, joined laterally, and 

 projecting on each side, where the terminations are transparent, 

 while the body is opake and white. Another variety consisted of 

 thin brittle plates, disposed side by side, each apparently single 

 plate being divided in two by an interstice not wider than the 

 thickness of a sheet of paper, having the internal surfaces 

 covered with extremely minute crystals. These masses have 

 been exposed to the action of the weather, as in some places the 

 plates are partly separated ; so that, when pressed betw^een the 

 fingers, they crack and break like thin shells, I likewise found 



