CHRONOLOGICAL ARRANGEMENT OF STRATA. 195 



EXPLANATION. 



Ideal section of the crust of the earth, showing the chronologi- 

 cal arrangement of the strata. 

 M Mantell. 

 B Buckland. 

 L Lyell. 



1. Alluvial or modern deposits, a. 2. do. do. Overlaying the coal 



2. Tertiary formations. formation. 



3. Cretaceous system, compris- b. 1. Granite veins in Granite, 

 ing the chalk, with & with- b. 2. do. do. passing through por- 

 out flints, chalk marl, gait pi lyry, gneiss, & mica schist, 

 or blue clay, Shanklin sand. b. 3. do. do. Overlaying Grau- 



4. TheWealden. wacke. 



5. The Oolite. c. Dyke of Trap, passing thro' 



6. The Lias. grauwacke and the lamina- 



7. The Saliferous, consisting of tions of marine limestones, 

 New Red Sandstone, Mag- forming basaltic columns, 

 nesian Limestone. c. 1. do. do. intersecting, and 



8. The Carboniferous System, overlaying an older dyke of 

 namely, the Coal measures, porphyry. 



the Mo.untain limestone. c. 2. do. do. overlaying the oolite 



9. The Devonian, or Old Red system. 



Sandstone. <c. 3. do. do. overlaying the chalk 



10. The Silurian, consisting of being lava of the extinct 

 marine limestones, shales, volcanoes of the Tertiary 

 calcareous flags. period. 



11. The Cambrian. d. Modern lava. 



* 



12. Mica Schist. , e. Cave in magnesian limestone. 



13. The Gneiss. f. Metallic veins in granite. 



14. Granitic System. g. Extinct volcano. 



15. Volcanic Rock. h. Artesian well. 



a. 1. Dyke of Porphyry in gran- 

 ite, passing through & over- 

 laying gneiss. 



