DINOSAURS. 33 



The Extinct Dinosaurs 



Order Dinosauria. 



Nearly allied to crocodiles are those remarkable extinct reptiles from the rocks 

 of the Secondary period, which include amongst their number the most gigantic 

 of all land animals, and likewise those members of the reptilian class which make 

 the nearest approximation in their organisation to birds. During that epoch of the 



RESTORATION OF THE [GUANODON. 



earth's history in which the Chalk and underlying Oolitic rocks were deposited, 

 when mammals were represented by a few small forms of lowly type these strange 

 reptiles were the dominant animals on land: some progressing in the ordinary 

 lizard-like manner, while others stalked on their hind-limbs like birds. To give 

 some idea of the enormous dimensions attained by some of these creatures, it may 

 be mentioned that the thigh-bone of one Bpecies measures 64 inches, while the total 



VOL. V.— 3 



