DOMAIN I. S1DEKOUS. 



Fair green, or yellowish green, with black spots. 



He also mentions a dark green porphyry, ol 

 which the trap base sometimes passes into crystals 

 of siderite ; while the large white crystals of fel- 

 spar are so numerous, that it might be called a 

 white porphyry. 



It is believed that green porphyry of this struc- 

 ture is found in Ireland, and in Cumberland, and 

 also in Norway. 



The ancient was probably found in Thessaly, 

 as will appear in discussing, under one point of 

 view, the Ancient Marbles in Domain V. 

 ftatement Saussure mentions the following : 



A porphyry with a base of greenish grey felsite, 

 with very small crystals of felspar, and some glo- 

 bules of lime ; the presence of the latter in so 

 hard a rock being regarded as singular. 1578. 



A singular porphyry of a chocolate colour, with 

 crystals of blue felspar. 1448. 



Not far from Frejus is a mountain of red por- 

 phyry, with some grains of quajctz. 1453. 



At Esterelle, between Nice and Frejus, are 

 rocks of porphyry, the base being of the colour of 

 wine lees. 1436. 



P DnrSc e e s f ^ e ^ so * ves ^ ie following account of the por* 

 phyries which he observed in pebbles, in the bed 

 of the river Durance, which has been long cele- 

 brated for its variolites. 



