Dr. FiTTON on the Strata beloio the Chalk. 105 



(4.) Combining these sources of distinction, the following arrangement and 

 subdivisions may be adopted, the nomenclature of which, however exposed to 

 criticism, is now probably too well established to be changed without incon- 



venience*. 







"Chalk . . . . 



r Upper. 

 <( Lorver. 



< 



, Green-sand 



. Marly. 



' Upper green-sand, 

 \ Gault. 



Wealden . • 



\_ Lower green-sand. 

 f Weald-clay. 

 -^ Hastings sands. 

 _ Purbeck strata. 



• 



~ Portland stone. 





Part of the 



Portland sand. 



Fossils, marine : species nu- 

 merous. 



") Fossils, for the greater part, 

 y of fresh water : species 

 J few. 



"1 



^„.,„, I Fossils, marine : species nu- 



OoLiTic Series ] Kimmeridge and Weymouth clay and sand. C merous. 

 L Oxford oolite (Coral rag). J 



(5.) I proceed now to describe the Sections of these strata, beginning with 

 the coast of Kent; and 1 shall connect with each section a list of such fossils as 

 I have either found myself, or obtained on good authority from the places men- 

 tioned. The whole of the shells in these lists have been examined and named 

 by Mr. James Sowerby, by whom also the drawings of the supposed new 

 species were made, and the annexed engravings executed f. It is right to 

 mention this explicitly, both that I may take the opportunity of expressing 

 my acknowledgments for Mr. Sowerby's valuable and assiduous cooperation, — 

 and that, being myself but very slightly acquainted with Conchology, I may 

 place the portion of the following pages which relates to that subject on 

 better authority than my own. 



Vicinity of Folkstone, Kent. 



(6.) The small map, (Plate VII. fig. 1.,) reduced from the Ordnance Survey, 

 represents the country in the immediate neighbourhood of Folkstone and 



* I have stated in another place (Annals of Philosophy, vol. viii. pp. 461, 462,) some objections 

 to the employment of names for geological strata, which refer to characters not essentially con- 

 nected with the structure or position of the objects to be designated. But the term green-sand, 

 however faulty, besides the universal use of it in England, has been adopted both in Germany and 

 France ; — where, however, it may be regarded, in some measure, as free from the disadvantages 

 of a significant name. 



t Plates XI., et seq. 

 VOL. IV. — SECOND SERIES. P 



