EARTH DRAGONS. 189 



of a double crest. The largest of these plates is 

 two feet high, and this probably does not repre- 

 sent their full size since they were almost 

 certainly invested in a horny sheath. The tail, 

 some ten feet long, was armed with a formidable 

 array of spines, forked at the top, and some of 

 them as much as three feet in length, with a 

 diameter of six inches at the base ! Whether 

 the sides of the body were also protected by 

 bony plates we do not know; neither can any 

 hazard a guess as to the use or probable need 

 of such an extraordinary armour as that which 

 surmounted the back. 



In not a few instances these wonderful reptiles 

 have left their mark upon the world in the shape 

 of footprints. ^4ncJiisaurus colurus, the carnivor- 

 ous beast mentioned earlier in this chapter, is 

 one of the species which has impressed the world 

 in this fashion ! For a long while these foot- 

 prints were believed to be those of birds, inas- 

 much as the marks of two feet only were dis- 

 cernible, and they had apparently but three toes 

 apiece. Undoubtedly these impressions bear an 

 unmistakable resemblance to those made by birds, 

 and as the Dinosaurs were then unknown, the 

 obvious inference was that birds had made 

 them. 



We now know their true origin, and there is 

 the less room for doubt since, at that period of 

 the world's history, birds had not appeared. 

 These " footprints on the sands of time" were 

 apparently made in soft, clayey soil, probably 

 near the margin of some pool or shelving river 

 bank, and then covered at high tide with turbid 



