380 
DR. MANTELL ON THE PELOROSAURUS. 
quarry represented in the frontispiece of my work on the Geology of the South-East 
of England, and that yielded to rny early researches the teeth of the Iguanodon and 
numerous other highly interesting remains. The bone was imbedded in the fawn- 
coloured sandstone that prevails in the Wealden of that part of Sussex, at the depth 
of 25 feet beneath the surface of the soil. The distal part of the bone, to the extent 
of 2 feet, was discovered in 1847, by Mr. Peter Fuller of Lewes, and some months 
afterwards the middle portion was found at a higher level ; a line of fault having 
traversed the rock and imbedded bone, and occasioned the subsidence of the portion 
previously met with. At length other fragments were discovered and extricated from 
the rock, and the whole replaced and cemented together in the admirable state in 
which the fossil now appears, by the intelligent collector in whose possession I had, a 
few weeks since, first the gratification of seeing this unique and stupendous relic 
from the Weald of my native county*. 
This bone is the right humerus, and bears a closer resemblance in its general cha- 
racter to the analogous element in the Crocodile, than to that of the Lacertians. It 
is 4^ feet long, and 32 inches in circumference at the distal extremity. It is in the 
ordinary state of mineralization of the bones from the Wealden sandstones, being 
of a rich umber colour, and very heavy from an impregnation of oxide of iron. The 
surface presents a smooth appearance, but upon close inspection is found to be finely 
striated : it evidently belonged to an animal arrived at maturity, but not aged -I-. 
The inferior or distal end, and nearly three-fourths of the shaft, are perfect; but a 
considerable part is wanting on each side the proximal extremity. Fortunately the 
base of the salient deltoid process, so characteristic of the humerus in the Crocodiles, 
is well-defined (Plate XXL fig. 1* c), and affords grounds for supposing that the upper 
part, which is deficient, did not materially differ from the recent type. 
The transverse fracture through the middle of the shaft (Plate XXL fig. Vf) has 
been left disunited, to show the large medullary canal which is filled up with con- 
creted sand ; as is usually the case in the long bones of the Iguanodon from the 
same locality. 
The thickness of the wall of the shaft at this section (Plate XXL fig. P) is 1 inch ; 
the transverse diameter of the medullary cavity 3 inches. Mr. Fuller informs me 
that the canal extended to within one-third of the head of the bone, as in the femur 
of the Iguanodon. 
The fossil, in its general form, is straighter than the humerus of the Crocodile, and 
the depressions between the condyles, both anteriorly and posteriorly, are relatively 
shallower. The surface for articulation with the fore-arm (Plate XXI. fig. 1 h) is 
* I cannot refrain from expressing my warmest thanks to Mr. Fuller, for the gratifying compliment paid 
me (though a personal stranger) as the original explorer of the Geology of Sussex, in allowing me to possess 
this interesting fossil, although he had previously refused several liberal offers. 
t Thin sections of the bone exhibit under the microscope the intimate structure beautifully preserved ; the 
bone-cells, and Haversian canals, are as distinct as in recent bones. 
