I860.] jf.hyis— mtoctxt; hocks of Tuscxsr. 483 



to find that largo quantities of the limestone in the neighbourhood 

 have been altered into dolomites, — the miemmite, a delicate greenish 

 rook of the same colour as aquamarine, being a double carbonate of 

 lime and magnesia. 



The copper from the serpentine is not associated with galena and 

 blende as with us, but is accompanied by many asbestiform minerals. 



The action of the serpentines on the limestones Which they have 

 traversed is very varied. Near Matarana 1 noticed the action on a 

 mouse-coloured limestone, where peroxide of iron had imparted a 

 brick-red. tinge to various parts of the mass. Within a yard or two of 

 the serpentine the rock had been apparently broken into fragments, 

 which had been cemented by delicate veins of serpentine flowing 

 into and filling up the cracks. This beautiful metamorphio rock, 

 called "Oflocalce," is, in fact, calcareous serpentine i it forms a rich 

 combination of colours — deep red and dark green, with interlacing 

 veins of pure-white calcareous spar. I would offer this explanation : 

 total decomposition of the limestone was prevented by the pressure; 

 the carbonic acid was partially expelled ; the heat decomposed the 

 carbonate of iron which was present in minute quantities, and com- 

 pletely peroxidized its protoxide of iron, which, being no Longer iso- 

 morphous with the pure carbonate of lime, was rejected as the Latter 

 crystallized out in various parts. It' I am not mistaken, this would 

 prove that the crystallization of carbonate of Lime in prisms (as 

 arragonite) only takes place within limited degrees of temperature, 

 ni, i,,, and below which the crystalline system is the //< vaf/onal. 



The copper-mine of kfonte Catini is found at the junction of the 

 gabbro rosso and the Miocene serpentine; the ore is invariably in 

 the Latter. It is one of the finest to be seen anywhere, and dates at 

 Least from the Florentine republioi Cosmo 1. reopened it in L562; 

 but it was not regularly worked, and, from want of experience, little 

 was dons until L837- The indications appear to have been very 

 favourable at the outset j but the successive proprietors failed to 

 realise theix desires, until the presi n1 company sunk to a depth of 

 400 feet . f'>l]..w in- the indications of ore ox •• vein" Lying B. and \\'.. 

 dipping at an angle of 16 B. j they then found an immense mass 

 of copper-ore, from whenoe they extracted i iboul LOO feet 



Lower a second deposil has Lately been reached, the breadth of which 

 1 should estimate at 80 feet. The various ores of copper are met 

 with in rounded masses, enveloped in serpentine : these nodules i on- 

 stitute a >]"•' Lee of conglomerate, some oftho massoe being ore,othexi 

 boulders of Berpentine, dispersed through a mati titio clay a 



The nodules on being broken open are found tooontain cha 

 or bornite, more rarely ootids of oopperi grey copper, and • 

 oopper. In physical appearanoe the ohaloopyrites differs entirely 

 from that obtained from our mines: thus it i.-. not Lamellar or 1 iy- 

 stallized, but hard, oompacti and massive, and has prcciscl) the 

 structure as bornite, into whioh it Insensibly passes bo the 

 nodules. This pyril mixed op wil 



pure, whioh can be aooounted fox by the expulsion of impui 



favoured, as it must have been, by the nodular QOaditioB of tho 



