160 
Transactions of the Society. 
The specimen noted from the Bed Chalk of Speeton (Burrows, Sher- 
bom and Bailey) appears to belong to this variety. It occurs in the 
Gault of Folkestone in zone x., very rare ; zone xi., 55 ft. from the 
top, very rare ; 50 ft., very rare ; 35 ft., very rare ; 12 ft. common ; 
6 ft., very common. 
Rhabdogonium excavatum Keuss (plate IV. fig. 9 a , b). 
Rhabdogonium excavatum Beuss, 1862, tom. cit., p. 91, plate xii. 
fig. 8. R. minutum (?) Burrows, Sherborn and Bailey, 1890, Journ. 
Boy. Micr. Soc., p. 559, plate x. fig. 8 a, b. 
This species has been found in the Gault of Folkestone (Beuss) ; 
the Gault of France (Berthelin) ; the Bed Chalk of Speeton (Burrows, 
Sherborn and Bailey) ; and the Chalk of Ireland (Wright). It is 
the most ubiquitous species of Rhabdogonium in the Gault of 
Folkestone, and is found in zone x., common ; zone xi., 55 ft. from 
the top, frequent ; 50 ft., rare ; 45 ft., frequent ; 40 ft., rare ; 35 ft., 
rare; 30 ft., rare; 25 ft. rare; 12 ft., very common; 6 ft., very 
common. 
Rhabdogonium Maertensi Beuss (plate IY. fig. 10 a, b). 
Rhabdogonium Maertensi Beuss, 1862, tom. cit., p. 56, plate v. 
% 4 - 
Beuss records this form from the Middle Hils-clay of Germany. 
At Folkestone one specimen only was found in zone ix. 
Makginulina d’Orbigny [1826]. 
Marginulina glabra d’Orbigny (plate IY. fig. 11 a , b). 
Marginulina glabra d’Orbigny, 1826, Ann. Sci. Nat., vol. vii. 
p. 259, No. 6 ; — Modele, No. 55. M. glabra Brady, 1884, Chall. 
Bep., vol. ix. p. 527, plate lxv. figs. 5, 6. 
The smooth varieties of Marginulina from the Gault are a some- 
what difficult series to separate. To the species M. glabra may be 
referred those examples which are nearly circular across the shell, and 
which have few and well-inflated chambers. It is, however, possible 
that the form next mentioned, M. insequalis Beuss, may, atter all, 
be a variety of the above, but with the initial series of chambers small, 
but subsequently increasing suddenly in size. Typical examples of 
M. glab'a appear to be rare in the Folkestone Gault. It is recorded 
from the Bed Chalk of Speeton (Burrows, Sherborn and Bailey); 
and altogether it is a well-distributed species in regard to geological 
time. Found in zone xi., 45 ft. from the top, very rare; 40 ft., 
very rare. 
Marginulina insequalis Beuss (plate IY. fig. 12). 
Marginulina insequalis Beuss, 1860, Sitzungsb. d. k. Ak. Wiss. 
Wien, vol. xl. p. 59, plate vii. fig. 3. M. insequalis Beuss, 1862, 
