THE IGUANODON. 313 



the Wealden at Sandown Bay, and at Brook and 

 Brixton. The vertebrae are invariably deprived 

 of their processes ; even the neural arch is in 

 general destroyed, and the waterworn body, or cen- 

 trum of the bone, alone remains.* The specimens 

 are commonly permeated with pyrites, and, in 

 consequence, are of great weight. The long 

 bones of the limbs are for the most part mutilated, 

 and but seldom have an articulating extremity so 

 perfect as to indicate the individual bone. Some 

 of the fragments, however, retain characters suffi- 

 ciently recognizable, and have unquestionably be- 

 longed to reptiles of enormous size. I obtained 

 from Sandown Bay the lower half of a tibia (large 

 bone of the leg), having the extremity that articu- 

 lates with the foot perfect ; the circumference of 

 this bone is four times that of a perfect tibia of a 

 young Iguanodon, which is one foot long : when 

 entire, its length must therefore have been nearly 

 four feet. The corresponding thigh-bone, estimated 

 from the relative proportions of a femur and tibia 

 in juxtaposition, would be a foot longer: the 

 entire length of the leg and thigh to which the 

 Sandown fossil belonged, must consequently have 

 been upwards of nine feet. 



* As shown in lign.ISS, fig. 8, p. 697, "Medals of Creation," vol. ii. The 

 perfect form of a caudal vertebra of the Iguanodon is represented in fig. 3 of 

 the same lignogiaph. 



