178 
BELEMNITES elongatus. 
TAB. DXC .—Jig. 1. 
Spec. Char. 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. pi. VII. / 6. 7. & 8. BeBlain- 
ville, Mem. sur les Belemn. p. 95. 
A Belemnite. Joshua Platt, Phil. Trans . 
vol. liv. p. SS ( with a figure). 
A great 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 opi- 
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. 
