178 
BELEMNITES elongatus. 
. TAB. DXC.—fig. 1. 
Spec. Cuar. Slender, cylindrical in the middle; 
gradually expanding to a broad base one way, 
and tapering’to a point the other; round, and 
free from furrows; the chambered cavity two- 
thirds the length of the shell. 
Syn. B. elongatus. Miller, Geol. Trans. 2d series. 
vol. II. p.60. pl. VIL. f.6.'7. & 8. DeBlain- 
ville, Mém. sur les Belemn. p. 95. 
A Belemnite. Joshua Platt, Phil. Trans. 
vol. liv. p. 38 (with a figure). 
————_——e 
A creat portion of the shell of this Belemnite is so thin 
as to give rise to the opinion that only part of the cham- 
bered cavity (the alveolus) is covered by the fibrous coat 
(guard or sheath); and that the last formed chamber, 
whose sides would principally consist of this coat, is not 
proportionally larger than the preceding one,—an opis 
nion that has been formed from the examination of im- 
perfect specimens, and influenced by the idea that the 
alveolus may be independent of the guard. The cylin- 
drical portion of the shell extends for about one fourth 
of its length, and is over the extremity of the cavity. 
The diameter of the base when perfect nearly equals a 
quarter of the length. 
Found in the Lyas Clay at Lyme, Charmouth, and 
near Bath. The specimen figured was lent in 1814 to Mr. 
Sowerby by the much-to-be-lamented friend to science 
Sir Joseph Banks, to whom it had been sent the year 
before by Mr. Bevan, who obtained it from the Crick 
Tunnel near Daventry, in Northamptonshire. 
