Foraminifera of the Gault of Folkestone. By F. Chapman. 9 
Pulvinulina spinulifera Reuss sp., plate II. figs. 1 a-c. 
Botalia spinulifera Reuss, 1862, Sitzungsb. d. k. Ak. Wiss. Wien, 
vol. xlvi. Abtli. i. p. 93, pi. xiii. figs. 3 a and h, 4 a-c, 5 a-c. Epi- 
stomina spinulifera Uhlig, 1883, Jakrb. k. k. geol. Reichsanst., vol. 
xxxiii. p. 768, pi. vii. figs. 5-7. Pulvinulina spinulifera Prestwicb, 
1888, Geology, vol. ii. p. 278, fig. 144 b. 
Reuss refers to the extreme variability of this species. The peri- 
pheral edge of the test is usually scalloped or notched, and the cusps 
are sometimes greatly produced. The septation is very pronounced ; 
-that of the superior surface is often prominent with each riblet notched, 
in others not so prominent, but with the central areas of the chambers 
excavate. On the inferior side of the shell the septal ribs are very 
prominent, sometimes forming keel-like projections. The umbilical 
boss on the inferior surface is excavated, and has from one to as many 
as five or six deep depressions. In P. spinulifera the secondary 
aperture is shorter and more gaping than in the preceding species. 
On examining the series of specimens of P. spinulifera in their 
sequence of distribution through the Gault beds at Folkestone, one is 
struck by an evolution in the form. That is to say, from zone i. and 
onwards to zone vii. they gradually increase in size and strength of 
ornamentation. Here, and in zone viii., they attain their greatest 
development; but after this, to zone xi. 55 ft. from the top, they 
gradually decrease in size, and appear to be absent from the higher 
.zones. 
This species was found by Reuss to be the most abundant in the 
Gault of Folkestone, and this is more or less the case in a few par- 
ticular horizons. But it is seen to be much restricted in its distribu- 
tion when the Folkestone Gault is examined throughout. 
P. spinulifera has been observed in the Ornatus- clays, Oxfordian 
of Russia (Uhlig) ; and was originally described from the Gault of 
Folkestone (Reuss) 
It occurs at Folkestone in zone i., spec, a, frequent ; zone ii., 
spec, c, very rare ; zone v., frequent ; zone vi., common ; zone vii., 
very common ; zone viii., common ; zone ix., frequent ; zone xi., 55 ft. 
from the top, common. 
Rotalia Lamarck [1804]. 
Botalia Soldanii d’Orbigny sp. var. nitida Reuss, plate II. figs. 
.2 a-c. 
Botalina nitida Reuss, 1844, Geogn. Skizze Bohmen, vol. ii. pt. i. 
p. 214. Id., 1845-46, Verstein. Bolnn. Kreideform., part i. p. 35, 
pi. viii. fig. 52 ; pi. xii. figs. 8, 20. Placentula nitida Berthelin, 
1880, Mem. Soc. Geol. France, ser. 3, vol. i. No. 5, p. 69, pi. iv. figs. 
11 a-c. Discorbina oligostegia Perner, 1892, Foraminifery Ceskeho 
Cenomanu (Palaeontographica Bohemias No. 1), p. 65, pi. x. figs. 5 a, b. 
