cxx Report of the Mineralogical Survey [No. 126*. 



associated with iron pyrites, (hexahedral iron pyrites.) These minerals, 

 particularly the latter, are often found imbedded in the potstone. Some 

 part of the galleries are cut in the dolomite rock, part in the potstone, as 

 the two rocks are continually interchanging, so that a gallery begun in 

 the former will, after 20 or 30 yards, be found to be in the latter. The 

 copper evidently traverses both rocks, and as far as the miners' accounts 

 can be trusted, is in veins. 



261. Till the publication of Professor Moh's system, great confusion 

 existed on the subject of these two mineral species. We have in some of 

 our most approved system-mongers, long and laboured articles, consist- 

 ing of many pages of description, tending to shew, that massive talc 

 was something different from potstone, and these again from soapstone ; 

 yet if we examine their several qualities, we shall find them identi- 

 cal. Professor Mohs, with the judgment which he has shewn through- 

 out his work, at once rejected futile distinctions that were without 

 differences, and has not hesitated to connect, as mere varieties, scaly talc 

 and potstone. The truth of his views, if they required confirmation, 

 would be found every where in these mountains, where an uninterrupted 

 series of gradations may be traced, from the most perfectly amorphous 

 potstone, through talc slate to the scaly mineral, usually considered a 

 distinct species. Previously to the publication of that excellent work I 

 had found so much difficulty in reconciling the contradictory accounts 

 of mineralogists, that I determined to form a collection of the various 

 types of this mineral, and in consequence, had satisfied myself, that there 

 is in reality no difference whatever in essential character amongst the 

 varieties, which hitherto have figured as distinct species. The inac- 

 curate determination of specific gravities by early writers, servilely 

 copied by their successors, has been partly the cause of this and many 

 other of the opprobia of mineralogy. The following determination of 

 this element, obtained from the specimens above alluded to, will serve 

 to shew, how absolutely the same it is in the different varieties, and to 

 confirm the accuracy of the limits fixed by Professor Mohs, viz. 2.7, 2.8. 



White potstone, (Seera Mine,) 2,712 



Black ditto, (Shergarury,) 2.76 



Greyish ditto, (Seera,) 2.76 



Yellowish soapstone, (Kuree,) 2.79 



Do. very steatic, (ditto,) 2.74 



