ROCK-METAMORPHISM. 



A. SILACID OPHITES*. 

 Serpentinytes. 



Talc-schists, Rensselaeryte (potstone). 

 Sepiolytes, Magneso-argillyte (" Argile magnesienne/" 

 Delesse) . 



a. Sub-silacid Ophites f. 

 Chlorargillytes. 

 Agalmatolytes. 



Chlorite-schists, Hydro-phlogopiteschists. 

 Talc-gneisses (Protogines) . 



Peridolytes(Lherzolyte_,Dunyte,Picryte,, Ossipyte,&c.) . 

 Ophi-euphotides . 



B. SlLO-CARBACID OPHITESj. 



Oplii-calcites. 

 Ophi-magnesites . 

 Ophi-dolomites. 



b. Sub-silo-carbacid Ophites . 

 Malacolophytes. 

 Hemithrenes. 

 Calci-micaschists. 

 &c. &c. 



The first section (A) graduates through certain of its members 

 into ordinary metamorphic rocks hornblendic, augitie, and 

 other gneisses, and the various crystalline schists; also into 

 euphotides, diorites, dolerites, and related plutonic masses. 

 There are serpentinous schists (chlorargillytes) that link the sub- 

 section to common clay-slates ||. 



The second section (B) is closely allied to the carbacid meta- 

 morphics dolomites and carrarites ^f . 



* Composed essentially of siliceous minerals. See ' Geological Magazine/ 

 January 1873, vol. x. 



t The subdivisions a and b contain the least amount of water. In a 

 alumina and oxides of iron are present. 



J Consisting of mineral silicates and carbonates. 



Serpentine (or a related mineral) is usually a subordinate constituent in 

 this subsection. 



|| See a paper by J. Arthur Phillips in ( Philosophical Magazine/ February 

 1871. 



5[ The statuary-marble of Carrara and other places. 



