FOSSILIFEEOUS FORMATIONS. 



723 



filtrated carbonate of lime occur in the north-east of Arran, which 

 contain numerous stems, branches, and fruits of carboniferous plants. 

 These represent the remains of successive forests which grew on this 

 locality, and were one after the other destroyed by the ash showers 

 poured forth from a neighbouring volcano during its intermittent 

 periods of activity. 



Fossil remains are extremely rare in certain rocks, which, from the 

 changes they have undergone, were denominated by Hutton metamor- 

 phic. These include Gneiss and Mica-slate, which are stratified rocks 

 subsequently altered by the effects of heat, having been so completely 

 metamorphosed that the traces of organisms have been nearly obliter- 

 ated. Nevertheless, recognisable traces of plant and animal remains 

 have been found in what were recently thought to be azoic rocks. 

 The absence of organic remains in rocks, howeyer, is not always 

 sufficient to enable us to state that these rocks were formed before 

 animals or vegetables existed. 



The stratified rocks which contain fossils have been divided into 

 three great groups, the Palaeozoic (TaXa/os, ancient, and ^(u^, life), 

 the Secondary, and the Tertiary ; or into Palaeozoic and Neozoic {viog, 

 young, Z,m, life) groups, the latter, including the Mesozoic (f^KSog, 

 middle) and the Cainozoic (xams, fresh). The formations included 

 under these are exhibited in the following table, taken from Lyell's 

 Manual of Geology : — . 



1. Recent. 



2. Post Pliocene. 



3. Newer Pliocene. 



4. Older Pliocene. 

 6. Upper Miocene. 

 6. Lower Miocene. 



. 7. Upper Eocene. 



8. Middle Eocene. 



9. Lower Eocene. 



10. Maestricht Beds. 



11. White Chalk. 



12. Chloritic Series. 



13. Gault. 



14. Neocomian. 



15. Wealden. 



16. Pvirheck Beds. 



17. Portland Stone. 



18. Kimmeridge Clay. 



19. Coral Eag. 



20. Oxford Clay. 



21. Great or Bath Oolite. 



22. Inferior Oolite. 



23. Lias. 



24. Upper Trias. 



25. Middle Trias. 



26. Lower Trias. 



I Post Tertiary, 

 { Pliocene. 



1 



Miocene. 



Eocene. 



- Cretaceous. 



Tertiary 



or 

 Cainozoic. 



}- Jurassic. 



Triassic. 



Secondary 



or 

 Mesozoic. 



Neozoic. 



