THE GEOLOGICAL RECORD 217 



tiles, must, with smy reasonable speed of change, have required 

 an enormous lapse of time, yet all these had their origin seem- 

 ingly during the same period. Some account of the strange 

 animals whose abundance and variety so especially character- 

 ised the Secondary period will now be given. 



Order — Dinosauria 



Some of the best known of these reptiles have been found 

 in our own country, and we will therefore begin with the 

 Iguanodon, of which teeth and bones were found near Maid- 

 stone (Kent) by Dr. Mantell in the early part of the last 

 century, but no complete skeletons have been found. A 

 closely allied species from Belgium of the same age (the 

 Wealden) is here figured (Fig. 50). It was about thirty foot 

 long, and is believed to have walked chiefly on its hind feet, 

 and to have fed upon the foliage or fruits of good-sized trees. 

 As shown in the restoration of the animal in its supposed usual 

 attitude when alive (Fig. 51), it would stand about fourteen 

 feet high. The fore-limbs are comparatively small, termi- 

 nating in a hand of five fingers, the thumb being represented 

 by a bony claw. The much longer hind legs, however, have 

 feet with only three toes, much resembling those of running 

 birds, and numerous impressions of such feet have been found 

 in rocks of the same age, hence the group to which it belongs 

 has been named Ornithopoda or '^ bird-footed.'' From the 

 character of these it seems probable that the animal would 

 walk on all fours and leap with its hind legs in the manner 

 of a kangaroo. 



The skull as shown by Fig. 52 is three and a half feet long, 

 and the numerous close-set serrated teeth seem well adapted 

 for grinding up large quantities of vegetable matter. The 

 deep compressed tail indicates that it may have been used for 

 swimming, and that the animal frequented lakes or marshes, 

 and perhaps escaped its enemies by taking to the water. It 

 appears to have had no protective armour. 



Another group was named Stegosauria, " plated lizards," 



