CLASSIFICATION OF ROCKS. 



Artificial System. 



TERTIARY CLASS. 



Lacustral: I 

 marine, or 

 fresh water; 

 or ./Estuaries, 

 elevated. 



r 



i 



'! 



Limestone 



Sandstone 



Chert. Millstone 



Shale 



Clay 



Marl 



Gypsum 



1A11 fresh water or all 

 , marine : or uncertain 

 ^successions of marine 



Jand. fresh water strata. 

 With organic lignites. 



Natural 

 System. 



Class 7. 



ALLUVIAL CLASS. 



Marine. 



Antient, Elevated : indurated, 

 Marl of Italy, &c. 

 loose. Italy, \vith 

 marine remains. Elsewhere ? 

 Of the present ocean, under pro- 

 trusion and retirement, or ele- 

 vation : false and presumed ter- 

 tiary strata, with woody lignites. 

 Coral: Islands of Pacific, &c. elevated or not. 



Class 8. 



Terrestrial. 



Local : 



Soil. 



)with 

 woody 

 lignites. 



Loose: of various 



materials. 



<5eneral: under antient 

 elevations and 

 currents 

 from fluviatile 

 transportation 



from local disintegra- 

 tion ; at rest, or moved. 

 From do. and transportation 



through rains. 

 Sand. From winds. 

 Solid. 



Travertine ; of Italy, &c. 

 Coral sandstones. Marine 

 and terrestrial together. 

 West Indies, &e. 

 Rocky strata, as in Chap. 7, 

 of lakes drained or filled, 

 not elevated. 

 Marl of lakes. 

 Terrestrial marl. On dry 



calcareous surfaces. 

 Peat. With submerged 

 wood. 



Class 9. 



VOLCANIC CLASS. 



Lava 

 Scoria 

 Pumice 

 Tufa. 



Class 10. 



PWith resemblances to por- 

 phyry, amygdaloid, basalt, 

 &c. in the trap rocks. 



