Foraminifera of the Gault of Folkestone. By F. Chapman. 575 
This species is easily recognized by the thickened growth of the wall 
of the shell, especially in the last few whorls, which are generally 
superficially puckered. Moreover, the sections in some of the older spe- 
cimens show the shell to be markedly biconcave. It appears both in 
the Lower and Upper Gault, but is more characteristic of the higher 
beds, where it is also better developed in point of size. Zone iii., 
very rare ; zone iv., common ; zone ix., very rare ; zone x., very rare ; 
zone xi., 55 ft. from the top, frequent ; 50 ft., common ; 45 ft., very 
rare ; 40 ft., common ; 30 ft., very rare ; 25 ft., very rare ; 12 ft., 
frequent ; 6 ft., rare. 
Cornuspira involvens Reuss, plate IX. figs. 12 a and h. 
Operculina involvens Reuss, 1849, Denkschr. k. Ak. Wiss. Wien, 
vol. i. p. 370, plate xlv. fig. 20. Cornuspira involvens Reuss, 1863, 
Sitzungsb. k. Ak. Wiss. Wien, vol. xlviii. p. 39, plate i. fig. 2. 
The shell of this species is biconcave, and the whorls increase 
rapidly in size towards the margin. A variation may be traced from this 
form to C. cretacea by the shell losing its roundness, consequently less 
embracing,- and the surface becoming puckered. The earliest strata 
in which it has hitherto been found are the Septaria clays of North 
Germany, the Baden Beds of the Vienna Basin, and the Clavulina- 
Szaboi Beds of Hungary. Zone iii., very rare ; zone v., very rare ; 
zone vi., very rare ; zone xi., 55 ft. from the top, rare ; 50 ft., very 
rare ; 12 ft. very rare. 
Cornuspira foliacea Philippi sp., plate IX. figs. 13 a and K 
Orhis foliaceus Philippi, 1844, Enum. Moll. Sicil., vol. ii. p. 147, 
plate xxiv. fig. 26. Cornuspira foliacea Parker and Jones, 1865, 
Phil. Trans., vol. civ. p. 408, plate xv. fig. 33. 
The shell is uniformly thin. The Gault specimens do not exhibit 
so sudden an increase in the width of the last turn or so of the shell 
as do the typical recent specimens. Zone iv., very rare ; zone xi., 
55 ft. from the top, very rare ; 45 ft., very rare ; 30 ft., very rare. 
