•388 Royal Society. 



ROYAL SOCIETY. 



March 23, 1848. — " 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 Wiltshire." 

 By Gideon Algernon Mantell, Esq., LL.D., F.R.S., Vice-President 

 of the Geological Society. 



The author states, that a line of railway now in progress of con- 

 struction to connect the large manufacturing town of Trowbridge 

 with the Great Western, being part of the Wilts, Somerset, and 

 Weymouth line, traverses extensive beds of the Oxford clay of the 

 same geological character as those at Christian-Malford in the same 

 county, which furnished the remarkable fossil cephalopods described 

 by Mr. Channing Pearce under the name of Belemnoteuthis, and by 

 Professor Owen (in a memoir which received the award of a Royal 

 Medal of this Society), as the animals to which the fossils commonly 

 known by the name of Belemnites belong. 



The son of the author, Mr. R. N. Mantell, being engaged in these 

 works under the eminent engineer Mr. Brunei, availed himself of the 

 opportunity to form an extensive and highly interesting collection of 

 the fossils of the Oxford clay, and other oolitic deposits cut through 

 or exposed by the engineering operations. Among those transmitted 

 to the author are many illustrative examples of Belemnoteuthes and 

 Belemnites ; some of which confirm the opinions entertained by the 

 late Mr. C. Pearce, Mr. Cunnington, and other competent observers, 

 that the body and soft parts, with the cephalic uncinated arms, &c. 

 of cephalopods, obtained from Christian-Malford by the Noble Pre- 

 sident and Mr. Pearce Pratt, and referred by Professor Owen in the 

 memoir above-mentioned to the Belemnite, belong to a distinct 

 genus — the Belemnoteuthis. 



The author describes and figures several perfect examples of the 

 phragmocone of the Belemnoteuthis, and institutes a comparison be- 

 tween them and a beautiful example of the phragmocone of a belem- 

 nite occupying the alveolus of the guard; and defines the essential dif- 

 ferences observable in the form and structure of these chambered cal- 

 careous cones. He especially points out as distinctive characters of 

 the phragmocone of the Belemnoteuthis, two flat longitudinal ridges 

 which extend upwards from the apical extremity, and the granulated 

 and striated external surface of the epidermis. The phragmocone 

 of the Belemnite has a smooth surface, is destitute of any lon- 

 gitudinal ridges, and terminates at the apex in a very fine point, the 

 axis being in an oblique direction. 



The author next describes a remarkable specimen of a Belemnite, 

 twenty-two inches in length, in which the osselet or guard, phrag- 

 mocone, and capsule or receptacle, are preserved in connexion. In 

 this fossil is demonstrated, for the first time, the upper or basal ter- 

 mination of the phragmocone, with two elongated calcareous pro- 

 cesses extending upwards from the margin : these are analogous in 

 form and position to the prolongations from the peristome of the 



