162 
Transactions of the Society, 
In the general contour of the shell this species resembles M. soluta 
Reuss, but that the latter has the surface of the shell quite smooth, 
and the aboral end is not mucronate. M. Folkestoniensis is found 
in zone v., very rare ; zone x., very rare ; zone xi., 50 ft. from the 
top, very rare ; 35 ft., very rare ; 25 ft., rare. 
Marginulina aspera (plate IY. fig. 18). 
The shell consists (in the specimen found) of two chambers, both 
flask-shaped and well inflated, the last chamber with a long-necked 
orifice. The surface of the shell is decorated with conspicuous 
prickles, not very thickly distributed. Length 1/60 inch. 
This species is similar in the decoration of the surface of the shell 
to M. armata Reuss,* but is distinguished from the latter by the 
great obliquity of the chambers, One specimen only, found in zone 
xi., 6 ft. from the top. 
Marginulina tenuissima Reuss (plate IV. fig. 19). 
Marginulina tenuissima Reuss, 1862, Sitzungsb/d. k. Ak. Wiss. 
Wien, vol. xlvi. p. 61, plate v. fig. 18 ; p. 92, plate xii. fig. 12 
( M . tenuissima var. Reuss). 
This species was recorded by Reuss from the Minimus- clay of 
North Germany, and the variety of the type was also recorded by 
that author from the Gault of Folkestone. There seems, however, 
no occasion to separate the two forms figured by Reuss, since the 
series of specimens from Folkestone now under discussion shows 
all gradations with regard to the relative height and breadth of the 
chambers of the shells, and the number of the fine riblets. This 
species is found at Folkestone in zone xi., 55 ft. from the top, very 
rare ; 45 ft., very rare ; 35 ft., very rare ; 30 ft., very rare ; 12 ft., 
very rare. 
Marginulina seguivoca Reuss (plate IY. fig. 20). 
Marginulina seguivoca Reuss, 1862, tom. cit., p. 60, plate v. 
fig. 17. 
This species is probably the commonest of the Gault Marginulinse , 
and is easily distinguished by the thinness and paucity of its costae. 
It has been previously recorded from the Minimus-clay of North 
Germany (Reuss) ; and from the Gault clay of France (Berthelin). 
At Folkestone it seems most characteristic of the Lower Gault. It 
is found in zone i., specimen h, very rare ; zone ii., specimen a, fre- 
quent; zone ii., specimen h, very rare ; zone iii., very common ; zone 
iv., very common ; zone v., frequent ; zone vi., very rare ; zone vii., 
rare ; zone viii., rare ; zone ix., very rare ; zone x., very rare ; 
zone xi., 55 ft. from the top, very rare ; 50 ft., very rare ; 25 ft., 
very rare. 
* Sitzungsb. cl. k. Ak. Wiss. Wien, I860, xl. p. 209, pi. vii. fig. 7. 
