of Devonshire and Cornwall, 179 



of very recent formation. This fact, which Dr, Kidd conceives to 

 be unique in its kind, appears less extraordinary, since the discovery 

 by Morichini of fluate of Ume in the enamel of some fossil ele- 

 phants' teeth, where it was mixed with phosphate of lime and 

 gelatine.* 



In the mine called Stony Gwynn, in the parish of St. Stephens, 

 violet fluor is found combined with vitreous quartz, phosphate of 

 lime, and yellowish foliated talc, forming a very hard and compact 

 rock, which constitutes the saalbande. This rock is certainly not the 

 same with that forming the mass of the mountain, although it re- 

 sembles it, thus demonstrating its antiquity. The middle parts of the 

 vein, in the same mine, although more recent, are however, in my 

 opinion, of much earlier formation than the greater number of the 

 other mines in Cornwall. It is a rock which has some resemblance 

 to the topaz-rock of Werner ; and is composed of a fine quartz, 

 more or less granular, with yellowish or white foliated talc. In 

 the middle part of the vein, there are frequent cavities, lined with 

 rock crystal, and crystallized apatite. This assigns a pretty remote 

 age to the last-mentioned substance as well as to the talc, which is 

 conformable with the ideas of Werner. The schorl rock may 

 perhaps be considered as a v^in-stone, or rather as forming a 

 saalbande. 



Carbonate of lime is of very rare occurrence in Cornwall ; I saw a 

 very fine specimen of schiefer-sparth, (slate-spar^ or chaux carbonatee 

 naccee of Haliy) in the collection of Mr. John Williams, which had 

 been found, I believe, in the tin mine of Polgooth. 



Such are the few observations I had to make on the ores and 



* Bronguiart, Tralte Elem. de Miner, tome i. p.2i6. 



z2 



