
Part III. Sect. iii. § 2.) CRETACEOUS. 815 
elevated, and how into pools of fresh and brackish water the leaves, 
insects, and small marsupials of the adjacent land were washed down. 
These evidences of terrestrial conditions are followed in the same re- 
gion by a vast delta-formation, that of the Weald, which accumulated 
over the south of England, while the older marine parts of the Cretaceous 
system were being deposited in the north. Hence two types of sedimen- 
tation occur, one where the strata are fluviatile or estuarine (Wealden), 
the other where they are marine (Neocomian). Arranged in descending 
order the following are the subdivisions of the English Cretaceous 
rocks : 
TABLE OF THE BRITISH CRETACEOUS SYSTEM. 

English Stratigraphical Subdivisions. Me Ce Zones. 




| 
is Oe | wanting. 
UprER CRETACEOUS. - 

= ( Toneut Be Horizon of eae one 
a ChallcofNorwich, . . . Retell S B. mucronata 
a | mucro- 
= HM oor fer | and B. quad- 
3 4 | rata. 
= : 
: See at age? ot Hie 
= ee REREP ALC. ee vo eee ee i | 5 Inoceramus 
Ss) ? o| tes orna- lingua and 
a RM tus. 
® few sponges. 
= » Broadstairs a ees Zone of Micraster cor-anguinum, var. 
Mavens piiee t's fet Y. M. cor-testudinarium. 
bb bP) 
(Hard Nodular Chalk of Dover, oa Zone of Holaster planus. 
| &c., “ Chalk Rock.” Ss 
Chaik without flints, Dover, &c. Fe Terebratulina gracilis. 
| Nodular Chalk of Shakespeare’s | 3 = Inoceramus labiatus (myti- 
Cliff, &e. | | loides). 
4 pe ieee 
Flints. 
Zone of Belemnites plenus. 


Grey Chalk of Folkestone, &e. 
| Totternhoe Stone Fag on gE eal of Ammonites 
rhotomagensis, 
oe 
Clone Wiel Lower Challewatheut 

{ S| Holaster : 
A, varians. 
3 <) re) : 
=, Be eeu »  Plocoseyphia 
g Chalk Marl pe \ meandrina. 
3 
= 
z Chloritic Marl pcamibpidse ©| Zone of “Craie glauconieuse” of 
S| Greensand) : .| 4a France. 
© 
5 \ 2) 
eat 
2.2 ) Warminster beds, &c. ‘ »  Pecten asper. 
58 Biackdown beds, &e. ; a Ammonites inflatus (rostratus). 
5 | | 1 pe EOS AS: 
+ ( Upper ; = | Ammonites cristatus, A. auritus, A. 
= 3| lautus. 
apy LOWERY inky ole Feem .|o | Hamites rotundus. See p. 819. 


