PHILOSOPHICAL TRANSACTIONS 
XII. Observations on some Belemnites and other Fossil Remains of Cephalopoda, 
discovered by Mr. Reginald Neville Mantell, C.E. in the Oxford Clay near 
Trowbridge, in Wiltshh'e. 
By Gideon Algernon Mantell, Esq., LL.D., F.R.S., F.L.S., 
Fie e- President of the Geological Society. 
Received March 2, — Read March 23, 1848. 
The group of argillaceous deposits of the Oolite or Jurassic formation, termed the 
Oxford Clay, has yielded some of the most interesting and instructive examples of the 
fossil remains of Cephalopoda hitherto discovered in England. Christian-Malford, in 
Wiltshire, is especially celebrated for the very perfect specimens of the soft parts of 
certain extinct forms of this class of molluscous animals ; examples having been 
obtained in which the body and muscular tunic or mantle, the cephalic arms with 
their uncinated acetabula, the capsule or external tunic of the eye-ball, the ink-bag, 
and the phragmocone, are preserved, and in some instances but slightly displaced 
from their natural relative positions and connections. The remarkable fossils de- 
scribed in the Memoir on the Belemnite* by Professor Owen, were procured by the 
Marquess of Northampton, Mr. Cunnington, and Mr. Pratt, from this locality. 
A branch line from the Great Western Railway to Trowbridge in Wiltshire, now in 
progress, in some parts passes over, and in others cuts through, the usual series of 
oolitic strata of that part of England ; namely, the Kimmeridge Clay, Oxford Clay, 
Kelloway Rock, and the Great Oolite with its subordinate beds of Cornbrash, Forest 
Marble, Bradford Clay, &c.'|' My son, Mr. Reginald Neville Mantell, who is 
engaged on this work under the eminent engineer I. K. Brunel, Esq., availed him- 
self of this favourable opportunity of collecting a very extensive suite of the fossils 
brought to light by the various cuttings and excavations required in the construction 
of the railway. This collection comprises many hundred specimens of the shells and 
* Philosophical Transactions for 1844, p. 65. t Wonders of Geology, 6th edition, p, 502. 
2 A 
MDCCCXLVIII. 
