LOWER CHALK—MICROGRAPHIC STRUCTURE. 267 
Family. 
Genera. 
No. of Species. 
Lituolidse 
Keophax - 
Fragments only 
Haplophragmium 
3 
Textulariidse 
Textularia - 
3 
Verneuilina - 
1 
Tritaxia - 
2 
Spiroplecta 
1 
Gaudryina - 
3 
Bulimina - 
7 
Pleurostomella 
- - 1 
Lagenidae 
Nodosaria 
2 
Marginulina 
1 
Vaginulina 
2 
Cristellaria 
4 
Globigerinidse 
Globigerina - 
2 
Rotaliidae 
Truncatulina - 
1 
Anomalina - 
2 
Rotalia - 
2 
As may be expected, there is considerable difference in the ap¬ 
pearance of the arenaceous forms, those of Maiden Bradley and 
Ventnor having their tests built of very coarse sand grains, whilst 
those of Shouldham are far more delicately constructed. Frag¬ 
ments of Reophax were common in the more sandy specimens of 
Maiden Bradley and Ventnor. Haplophragmium occurred both at 
Maiden Bradley and Shouldham, and probably is to be found in all 
localities under consideration. Tritaxia tricarinata, and Trit. 
pyramidata, and the Bulirnines occurred in all localities. Of 
the latter Bulimina Presli and Bulimina brevis were most abundant. 
Amongst Textularians were Textularia trochus, T. turris, and 
T. minuta, and these with Gaudryina pupoides complete the 
list of the commoner arenaceous forms. 
Of the others Anomalina ammonoides, Cristellaria rotulata, 
Rotalia Soldani , and Globigerina cretacea were the most promi¬ 
nent. The tests of the latter species were all very small. Spiroplecta 
anceps, a common form at Maiden Bradley and Bookham, does 
not occur in the more eastern samples. Individual specimens 
were least numerous in the sandy rock of Maiden Bradley and in 
the Chloritic Marl of Folkestone. 
In the Cambridge Greensand Professor W. J. Sollas found forms 
of Lituola , Lagena and Vitriwehbina very abundant, * genera which 
appear to be rare elsewhere. He also notes that Nodosaria 
Vaginulina, Frondicularia, Flabellina and Bulimina are common 
arenaceous forms. In 1899 Mr. F. Chapman published a com¬ 
plete account of the Foraminifera from the Cambridge Greensand 
enumerating 138 species and varieties belonging to 29 genera.j 
He observes that many of them, ‘‘ especially among the larger 
species, show a marked abrasion of their tests,” and he is 
“ strongly inclined to believe that a large proportion of the 
microzoic fauna has been derived from the upper beds of the 
See Quart. Journ. Geol. Soc., Vol. xxviii. p. 398 (1872). 
t Ann. Mag. Nat. His., Ser. 7., Vol. iii. pp. 48 and 302. 
