Determination of Diallage. 142 



the neighbourhood of a spring called the Kupplerbrann, from 

 which quarry the country around is supplied with a coarse kind 

 of very hard mill-stones. The rock contains in this quarry thin 

 layers of Quartz, filled with a great number of beautiful varieties 

 of the Carinthine of WERNER (hemiprismatic Augite-spar),of Kya- 

 nite, of Zoisite, of crystallised varieties of Rutile (peritomous 

 Titanium-ore), and of many other minerals we admire in collec- 

 tions. The same rock is also met with in the north part of 

 the same mountain ; and Professor MOHS has found it in his 

 travels through the Stirian and Carinthian mountains, to extend 

 to the Koralpe, and the more western parts of the Bacher, the 

 east end of which is occupied by the Gabbro described above. 



It would too far exceed the limits of the present paper to en- 

 ter into similar details upon another class of rocks, likewise called 

 Gabbro, or Euphotide, the chief ingredients of which are, not the 

 green, but the metalloidal Diallage (hemiprismatic Schiller-spar), 

 Labrador-felspar, and partly also Serpentine ; as, for instance, in 

 that from the Monte Ferrato, near Florence *. I only venture 

 to add a few remarks as to the last of these species. 



Serpentine has been pronounced by VON BUCK to be no- 

 thing else but a fine-grained mixture of Gabbro and Talc, an 



opinion rather too much the result of mere speculation, than 

 should ever be the case in a science connected with nature ; yet 

 the doubts respecting the existence of a particular species of Ser- 

 pentine, which he derives from this opinion, are strongly supported 



* According to the descriptions given by Drs HIBBEET and MAcCuLLocn, the 

 Diallage-rock from Shetland belongs likewise to this class. I cannot pass entirely 

 unnoticed their labours in ascertaining the geological positions of these rocks ; but 

 not yet having had an opportunity of examining the rocks themselves, and having 

 only recently become acquainted with the accounts published by Dr HIBBERT in lu's 

 Description of the Shetland Islands, p. 372., and by Dr MACCULLOCH, in the Quar- 

 terly Journal of Science, Literature and the Arts, vol. x. p. 103., I cannot at present 

 dwell any longer upon this subject, 



