50 M. Von Bucu on Gahhro. 



(geologically considered) with the serpentine formation, and 

 the last is in general anterior to the former. 



When extracting from M. von Buch's memoir, we have 

 thought it right to preserve the name given by him (after the 

 Florentines) to the rock of which he treats ; but we repeat, 

 tSiis rock is the one described under the name of Euphotide, 

 by M. Haiiy in his lectures, and by M. Brongniart in his 

 essay on the classification of rocks.* The term gabbro has 

 moreover been applied to " amphibole hornblende."+ That 

 of Saussurite, which has been proposed for jade, and which 

 could scarcely be adopted for that substance, whose present 

 name is so universally spread, would perhaps have been per- 

 fectly suitable, applied to a rock hitherto undescribed, and 

 to which de Saussnre had just called the attention of mine- 

 ralogists. Gabbro or euphotide exists without doubt in many 

 other countries than those where M. von Buch has observed 

 it. It appears to us that it has, as in the case of Silesia, often 

 been described by the German mineralogists under the name 

 of primitive greenstone (griinstein), many of whom, as we 

 have before observed, believe that diallage and hornblende 

 ought to be considered as a single species. We shall cite as 

 examples the greenstones of Harzeburger forst, of Baste, of 

 the valley of Radau, &c. in the N.E. part of the Hartz. 

 These rocks are certainly, or at least in part, euphotides.' 

 It is remarkable that they are associated with serpentine, 

 containing schiller spar (diallage metalloide) so well known 

 under the name of schillerspath or schillerstein of the Hartz. 



Euphotide and serpentine have been observed at the west- 

 ern extremity of Cornwall; the Lizard point is formed of it. 

 Observations on this subject are contained in Dr. Berger's 

 memoir inserted in the first volume of the Transactions of 

 the Geological Society of London.* 



* Journal des Mines, No. 199. 



+ Memoir on Basalt. Journal de Physique, 1787. 



* Professor Sedgewick has published a detailed account of the diallage 

 and other rocks of the Lizard district in the 1st volume of the Cambridge 

 Philosophical Transactions. A description and colcuied map of the 

 iame district is given by Mr. Majendie in the 1st volume of the Transac- 



