442 



excellent essays on stratification. To Mr. Farey I acknowledge con- 

 siderable obligations for his exceedingly liberal and unreserved commu- 

 nications on subjects connected with these inquiries. 



According to the actual observations of Mr. Smith, as given by Mr. 

 Farey, in his General View of the Agriculture and Minerals of Derby- 

 shire, Vol. I. p. Ill, the following are the upper strata which have been 

 discovered in this island, disposed in the order in which they occur. 



1. Sand. il 



2. Clay, with septaria. 



3. Sand, with shells, varying in thickness and in mixture with other 

 substances, 



4. Soft chalk with flinty nodules, 

 5 Hard chalk. 



6. Chalk marl. 



7. Aylesbury limestone. 



8. Sand and clay strata, in one of which is a dark coloured shelly 

 limestone, called Sussex marble. 



9. Woburn sand, in which is a stratum of fuller's earth. 



10. A thick clay, called the clunch clay. 



11. Bedford limestone* 



12. A thick clay. 



13. Rag-stone of Barnack, &c. 



14. Limestone and grey slate of Stunsfield, Colley Water, &c. 



15. Sand. 



16. Bath free-stone. 



17. Sand and clays. 



18. Maidwell limestone. 



19. Lias clay, containing the blue and white Lias limestone. 



20. Sand. 



21. Red marl. 



Beneath these follow the grit-stones and coal shales, and the alternating 

 limestones and toadstones. Parts of these inferior strata appear to have 

 been so raised and so denudated of their superincumbent strata, by some 



