of Mixed Rocks. xvii 



Principal varieties. 



Antique O Green compact, homogeneous, opaque paste, 



with crystals of green felspar. 



Varied O. Brownish ureen granular paste with crystals 



of white, grey, or green felspar. 

 (Tl»e Tourmalet in the Pyrenees. Bode in 

 the Hartz, Niolo in Corsica.) 



Species 3. AMYGDALOID. {Mandelstein, Werner.) 

 Some rocks improperly named variolites.* 



Paste of petrosilex, containing round nodules of petrosilex, 

 of a different colour from that of the paste. 



Principal varieties. 



Greenish A The tint generally green. / 



(La Durance.) 

 Gret a. 

 Red a. 



PoRPHYRlTic A A reddish paste containing small crystals of 



felspar and hornblende, with nodules. , , 

 (Orbicular porphyry of Corsica.) 



Species 4. EUPHOTIDE. (J/a%. Diallage rock.) 



Base of jade, petrosilex, or even of felspar, with numerous 

 crystals of diallage. The structure granular. 



(Corsica. Genoa, &c.) 



Genus 10. WITH A BASE OF PETROSILEX, 

 OR OF GRANULAR FELSPAR. 



Species 1. EUIIITE. (^cVjiubuisSGn. Some zceissfeiris. 

 Klingstein. Werner.) 



Base of rather pure petrosilex, containing mica and other 

 disseminated minerals. Structure either granular, fissile, or 

 imhedded. 



* Not only do the amygdaloids, as we here characterize them, differ 

 from variolites in the nature of their paste, in that of their nodules, and 

 in the relations of the formations of the two positions; but we moreover 

 see that they differ in their geological position. Our amygdaloids are 

 generally of a much more ancient formation than the variolites. All 

 therefore tends to separate these two species of rocks which have been 

 so much confounded. 



