384 
DR. MANTELL ON THE PELOROSAURUS. 
distal series which form a great part of the tail ; in these “ I'os en chevron ny est plus 
articuU, mais sondd, et fait corps avec elles^y 
The structure of the spinal column of the Mosasaurus therefore proves that ver- 
tebrae having the chevron bone articulated by two distinct facets (as Plate XXII. fig. 8), 
may be followed, in a more distal part of the caudal region, by a series with the 
haemapophysis anchylosed to the centrum (as in Plate XXIII. fig. 11). 
Femora and Tihice. — From the Wealden strata of Tilgate Forest, Hastings, and the 
Isle of Wight, I have seen fragments of the distal extremity of femora with medul- 
lary cavities, which, though too imperfect to admit of accurate determination, were 
obviously those of a gigantic terrestrial reptile, distinct from the Iguanodon and 
Megalosaurus. 
From Sandown Bay, in the Isle of Wight, I have the proximal end of a tibia of 
enormous size, the circumference of the head of the bone being 34 inches, a magni- 
tude surpassing that required for a tibia to articulate with the largest known femur, 
and presenting such deviations in form from the tibiae of the Iguanodon, as to render 
it highly probable that this bone belonged to the Pelorosaurus. 
Indications of the Pelorosaurus in the Oolitic strata. — The general accordance of 
the terrestrial fauna and flora of the Oolitic period, (as proved by the remains of land 
animals and plants imbedded in the fluvio-rnarine deposits of that formation,) with 
those of the Cretaceous and Wealden, renders it probable that vestiges of most, if not 
all, of the genera and species of land reptiles that occur in the latter will be found 
in the former strata. Thus as the Iguanodon, Pterodactyles, with Clathrarise and 
Dracsenee, are found in the Chalk, and the Megalosaurus, with Cycadese and Coniferse, 
in the Wealden, traces of the Pelorosaurus may be expected to occur in the Oolite. 
To ascertain this fact, I availed myself of the liberal permission of my friend the 
Dean of Westminster to examine his splendid collection, and I repaired to Oxford 
and diligently inspected the numerous specimens of Saurian remains which it con- 
tains, especially those from the W’ealden and Oolite. 
To avoid prolixity I will but remark, that among immense quantities of huge ver- 
tebrae and bones of the extremities of unequivocally marine Saurians, as proved by the 
cancellated structure of their centres, and which had been properly referred to Plio- 
saurus, Cetiosaurus, &c., there are portions of femora, vertebrae, and tarsal phalangeal 
and ungueal bones, which appear to be distinct from those of any established genus. 
I refer especially to several caudal vertebrae resembling that from Tilgate Forest 
(Plate XXIII. figs. 9 and 10), which are probably of the Pelorosaurus, SLXid large curved 
claw-bones, from 4 to 6 inches long. These were found at Chipping Norton, asso- 
ciated with vertebrae, &c. of Cetiosaurus, and were accordingly assumed to belong to 
the same genus of reptiles. 
But the specimens which come more immediately within the scope of this inquiry 
are portions of femora from Enstone, which appear to differ from those of the Mega- 
* Ossemens Fossiles, tome v. p. 327. Edit. 1824. 
