Serpentine and Didllage Rocks. 269 



tion the globular form and stellular structure of the porphyries 

 of Corsica and the Thuringerwald, of the pitchstones of Arran 

 and Meissen, and of the pearlstone of Hungary. These inte- 

 resting rocks generally border the greater masses of serpentine, 

 as is seen near to Genoa ; but they do not appear along the ser- 

 pentine hillocks of the marly and arenaceous deposite of east- 

 ern Liguria and Tuscany. 



Euphotide sometimes appears in isolated hills beside the ser- 

 pentine ; in other cases the rocks pass into each other, or they 

 are so interwoven with each other that the one rock forms dikes 

 or distinct veins in the other. The hills between Braco and Ma- 

 torana, in Liguria, afford a fine example of this appearance. 

 "The whole may be explained on the principle of the slow cool- 

 ing of the mass. 



Lastly, The numerous simple minerals met with in serpen- 

 tine do not occur in it every where. Diallage and asbestus, de- 

 rived from hornblende and augite, are of these by far the most 

 frequent. Garnets, augites, and hornblendes, are principally 

 met with in the small beds, as those of Portsoy, Heidenberg, 

 Fichtelgebirge. Chromate of iron occurs in the great bodies of 

 serpentine connected with the talcose formation, as in the island 

 of Unst in Shetland, central France, Golsen near Leoben, and 

 Kraubach in Stiria : the same is the case with the native copper 

 of America, &c. and the workable nests of pyrites at Monte 

 Ramazzo, near to Genoa. Magnesite abounds much in some 

 localities, as Hrubschitz in Moravia, Gurhof in Austria, Bal- 

 dissero, Castellamonte, &c. ; when this is the case, the serpen- 

 tine contains semi-opals and calcedony, as at Gersec in Mora- 

 via, and chrysoprase, as at Kozemutz in Silesia, and Besenoro 

 in Syrinia. These siliceous minerals are to the serpentine in 

 the same secondary relation as the small similar veins in the 

 granite, with kaolin and scapolite, at Hafnerzell in Bavaria. 



Are we to admit that there are five different formations of 

 serpentine ; and, consequently, that it has been erupted at five 

 different periods ? In this view we would have, first, a serpen- 

 tine, posterior to the marls and sandstones of the Appenines and 

 Carpathians ; a second, posterior to the transition red sandstone ; 

 a third, posterior to the greywacke ; a fourth, to the mica 

 slate ; and, a fifth, to the gneiss and leptinite. But has ser- 



