Unstratified Rocks. . 



The following arrangement, by M. Brongniart, is a useful 

 summary of the series of Unstratified Eocks, and is abridged 

 from Professor Phillips's ' Geology,' ia ' Cabinet Encyclo- 

 paedia,' vol. ii. p. 59. 



:mixed eocks. 



I. Cetstallized IsoiCEEOus Rocks, in which the cotutituent parts 



are equally Mended. 



A. Pelspathic Rocks, the characteristic mineral being Felspar 



Granite, Protogine, Pegmatic or Graphic Granite, Mimose. 



B. Homblendic Rocks, the characteristic mineral being Hornblende. 



Sienite, Diabase or Greenstone. 



II. Cetstallized Anisomeeocs Rocks, in which the conttituent 



parts are not equally mixed. 



A. Basis of Serpentine, with imbedded minerals. — OphioHte. 



B. Basis of Comean, with imbedded minerals. — Variolite, Yaldte. 



C. Basis of Hornblende or Basalt, with imbedded minerals. — Amphi- 



bolite, Basanite, Trappite, Melaphyre or Trap Porphyry. 



D. Basis of Petrosilex coloured by Hornblende. — Porphyry, Ophite, 



Amygdaloid, Euphotide. 

 B. Basis of Petrosilex or compact Felspar. — Emrite, Leptenite, 

 Trachyte. 



