150 PETRIFACTIONS AND THEIR TEACHINGS. CHAP. III. 



splendid skeletons of Plesiosauri spread out on slabs of grey 

 limestone in Cases D and E, are to be found in the strata in 

 a condition that would admit of their being even recognised 

 as organic remains by the uninstructed eye. On the con- 

 trary, mere shapeless masses of rock, with here and there 

 fragments of bone scarcely distinguishable from the surround- 

 ing stone, are in general the sole indications of these precious 

 monuments of distant ages, that have been enshrined for an 

 incalculable period, and which require the skill and labour of 

 the practised explorer to develop and render intelligible to 

 the comparative anatomist. 



The degree of distortion which the strong and massive 

 bones of the colossal reptiles of the Wealden have in many 

 instances sustained, is truly remarkable. Leg and thigh- 

 bones, and the bodies of vertebrae of enormous size, and 

 which were originally of a sub-cylindrical form, are found 

 twisted, contorted, and pressed almost flat, and yet with but 

 slight indications of fracture. It is clear that the skeletons 

 of the stupendous saurians must have been rendered plastic 

 by long maceration in water before the mud and sand in 

 which they were engulfed had consolidated around them, 

 and ere their tissues were permeated by mineral matter. 



The Maidstone Iguanodon, (Table-Case 23 of the plan, 

 ante, p. 138,) is a striking example of this kind; in the 

 entire series of bones exposed, there is scarcely one that is 

 not more or less altered by compression. The humerus and 

 thigh-bones especially, are completely distorted ; the ver- 

 tebrae pressed almost flat, or squeezed into abnormal shapes ; 

 one of the clavicles is twisted and thrown into the most 

 fantastic position ; and so great was the transformation the 

 bones had sustained, that although Mr. Bensted had spent 

 weeks in clearing out the most obvious masses of bone, and 

 had marked the relative connexion of the principal pieces 

 into which the specimen had been fractured by the explosion 

 of the rock, it was several months, and with the' aid of 

 a mason, before I succeeded in cementing the pieces together, 

 and restoring the fractured parts to their present state ; nor 

 could this have been successfully effected, had I not previ- 

 ously obtained perfect specimens of almost all the parts of the 

 skeleton of the Iguanodon, which in this instructive fossil 

 were found associated together for the first time, to guide 



