430 THE WONDERS OF GEOLOGY. Lbct. IV. 



the chevron bones, (b, b 9 ) are of great length ; the latter 

 have their bases so blended as to form but one face for 

 articulation with the truncated inferior angles of the body 



b 



Lign. 105. — Six caudal vertebra of an Iguanodon ; from Tilgate Forest. 



(One-sixteenth natural size.) 



a, a, Spinous processes, fifteen inches high, b, b, Chevron bones, imbedded in the 

 stone near their original articulation between two of the vertebra?. 



of the vertebrae, leaving a vertical and elongated channel, 

 for the passage of the large blood vessels of the tail. The 

 proportions of these elements of the caudal vertebras indi- 

 cate a great vertical development of the tail. In the beau- 

 tiful specimen before us (Lign. 105) of six united caudal 

 vertebrae, imbedded in a block of Tilgate grit, with both 

 the upper and inferior spinous processes displayed, these 

 characters are strikingly obvious. The width, or rather 

 height, of that portion of the tail to which these bones 

 belonged, must have been at least twenty-seven inches. 



