WEALDEN FORMATIONS. 41 



spongy at the centre. The proximal end is expanded, with a nearly flat articular 

 surface, the contour of which is broken by two longitudinal indentations ; the distal 

 end offers a well-sculptured trochlear articulation for the first phalanx. The bone of 

 the Maidstone Iguanodon (marked ' metatarsal' in the plate above cited) corresponds 

 with the shorter of the two bones above cited. 



Some of the phalanges, probably the middle ones, appear to have been singularly 

 abbreviated; but they have not yet been discovered in such juxtaposition with 

 undoubted Iguanodon's bones as to justify a more precise description of their characters 

 under the present head. 



Of the uppermost or proximal phalanges, one tolerably perfect specimen has long 

 been known to palaeontologists. It probably belonged to the left fore-foot of the 

 Iguanodon, and is from the Wealden iron-sand which forms the shore of the Isle of 

 Wight, east of Sandown Fort. This specimen, Tab. XVI, fig. 1, is described by 

 Dr. Buckland as a 'metacarpal bone' in the 'Geological Transactions,' vol. iii, 2d 

 series, p. 425 : it does not exhibit, however, any articular facet at the side of the 

 proximal end for junction with a contiguous metacarpal ; and at the distal end, instead 

 of a uniform convexity, it presents the trochlear combination of a vertical convexity with 

 a transverse concavity. The inference, therefore, as to the metacarpal bones of the 

 Iguanodon being much shorter and thicker than in any living crocodiles or lizards, 

 receives no support from the proportions of the present specimen. 



The following is the notice of the original specimen, in the memoir above quoted. 



" The first of these two new localities " (for fossil remains of the Iguanodon) " is on 

 the south coast of the Isle of Wight, in the iron-sand which forms the shore, a little east 

 of Sandown Fort, between high and low water. The most remarkable specimen I pos- 

 sess from thence is the gigantic metacarpal bone about to be described. The form 

 of this bone nearly resembles one in the collection of Mr. Mantell, which Cuvier saw, 

 and pronounced to be a metacarpal bone of the thumb of a reptile ; but much ex- 

 ceeds it in size, measuring 6 inches in length, 5 inches in width at its largest diameter, 

 and 16 inches in circumference at its posterior and largest extremity. Its weight is 

 nearly six pounds. 



" It is, I believe, the largest metacarpal bone which has been as yet discovered ; 

 and if we apply to the extinct animal from which it was derived, the scale by which 

 the ancients measured Hercules ("expede Herculem"), we must conclude that the 

 individual of whose body it formed a part, was the most gigantic of all quadrupeds 

 that have ever trod upon the surface of our planet. The corresponding bone in the 

 foot of the largest elephant is less than our fossil metacarpal by more than one half. 

 The bone represented by Mr. Mantell (PI. 14, figs. 4, 5, of his 'Fossils of Tilgate 

 Forest') approaches the nearest of all those engraved by him in this work, to our bone 

 from Sandown Bay. He considers his fossil to be most probably a metatarsal bone of 

 the Iguanodon, and states that he has one such bone which measures 4^ inches in 



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