308 
ELEMENTS OF GEOLOGY. 
CHAPTER XVIII. 
LOWEE CEETACEOUS OE NEOCOMIAIS^ FOEMATION. 
Classification of marine and fresh-water Strata.—Upper Neocomian.—Folke¬ 
stone and Hythe Beds.—Atherfield Clay.—Similarity of Conditions causing 
Reappearance of Species after short Intervals.—Upper Speeton Clay.— 
Middle Neocomian.—Tealby Series.—Middle Speeton Clay.—Lower Neo¬ 
comian.—Lower Speeton Clay.—Wealden Formation.—^Fresh-water Char¬ 
acter of the Wealden.—Weald Clay.—Hastings Sands.—PunfieldBeds of 
Purbeck, Dorsetshire.—Fossil Shells and Fish of the Wealden.—Area of 
the Wealden.—Flora of the Wealden. 
We now come to the Lower Cretaceous Formation which 
was formerly called Lower Greensand, and for which it will 
be useful for. reasons before explained (p. 282 ) to use the term 
“ Xeocomian.” 
LOWEE CEETACEOUS OE NEOCOMIAII GEOUP. " 
Marine. 
1. Upper Neocomian — Greensand of Folke-'' 
stone, Sandgate, and Hythe, Atherfield 
clay, upper part of Speeton clay. 
2. Middle Neocomian—Punfield Marine bed, ^ 
Tealby beds, middle part of Speeton clay. 
3. Lower Neocomian—Lower part of Speeton 
clay. 
Fresh-water. 
Part of Wealden beds of 
Kent, Surrey, Sussex, 
Hants, and Doi set. 
In Western France, the Alps, the Carpathians, Xorthern 
Italy, and the Apennines, an extensive series "of rocks has 
been described by Continental geologists under the name of 
Tithonian. These beds, which are without any marine equiv¬ 
alent in this country, appear completely to bridge over the 
interval between the Xeocomian and the Oolites. They may, 
perhaps, as suggested by Mr. Judd, be of the same age as 
part of the Wealden series. 
UPPEE NEOCOMIAN. 
Folkestone and Hythe Beds. — The sands which crop out 
beneath the Gault in Wiltshire, Surrey, and Sussex are some¬ 
times in the uppermost part pure white, at others of a yellow 
and ferruginous color, and some of the beds contain much 
green matter. At Folkestone they contfiin layers of calcare¬ 
ous matter and chert, and at Hythe, in the neighborhood, as 
also at Maidstone and other parts of Kent, the limestone 
called Kentish Rag is intercalated. This somewhat clayey 
