E. Neaverson—Foraminifera of the Hartwell Clay. 469 
Number of species. 
Chapman, 1897. Neaverson, 1921. 
LitvoLip2. Reophax : é 
Haplophragmium 
Thurammina . 
TEXTULARUDZA. Tritaxia. 
LAGENIDZ. Lagena . 
: Nodosaria 
Frondicularia 
Marginulina . 
Vaginulina 
Cristellaria 
Polymorphina. 
GLOBIGERINID™. Glohigerina 
ROTALIID. Pulvinulina 
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7 genera. 12 genera. 
5 
15 species. 36 species. 
In order to analyse the results Chapman’s list (Proc. Geol. Assoc., 
vol. xv, 1897, p. 97) is merged with the new record, as the Hartwell 
forms have not been fully described before. 
Thirty-seven species of Foraminifera have been found in the 
Hartwell Clay and associated clays. Of these one form is not 
specifically identified, so will not be further considered. Thirteen 
(or 36 per cent) of the remaining thirty-six species were recorded 
from Jurassic deposits older than the Hartwell Clay, whilst 
twenty-three (or 64 per cent) were not known below the 
Cretaceous before the publication of Chapman’s list. Further, 
twenty-two of the thirty-six species occur in the Gault of 
Folkestone, twelve in the Bargate Beds (Aptian) of Surrey, 
ten in the Speeton Clay of Yorkshire, and thirteen in the Lower 
Cretaceous of Germany. This confirms Chapman’s general 
statement that the Foraminifera of the Hartwell Clay “ present 
a facies comparable with that of the Neocomian (sic) and Gault ” 
The relation is seen more especially with regard to the Cristellarie, 
which are represented in the Hartwell Clay by eleven species, eight 
of which are characteristic Lower Cretaceous forms. Other Hartwell 
forms connecting with the Lower Cretaceous are Globigerina 
marginata, Vaginulina incompta, and Haplophragmium acutidorsatum. 
The Vaginuline, however, present a general Jurassic facies: the 
commonest species, V. harpa, with its strong longitudinal ribbing, 
forming a marked contrast with the typical Vaginuline of the Gault 
which possess projecting sutures and marginal angles. In V. discors 
of the Hartwell Clay the longitudinal ribbing is not so conspicuous, 
but the limbate sutures and margins are still lacking. Cvistellaria 
and Vaginulina are the dominant genera in the Hartwell Clay, and 
it is interesting to find the former represented by Cretaceous species, 
whilst the latter genus has a Jurassic aspect. 
It is more difficult to compare the Hartwell Clay Foraminifera, 
with those from older Jurassic deposits, as the latter have been 
somewhat neglected. The series from the Kimmeridge Clay and 
Oxford Clay of Bucks show a marked difference in the assemblage 
