TRIASSIC PERIOD. 



415 



The largest of the tracks was nearly two feet long ; and, from its 

 depth and the great length of stride, it is evident that the animal was 

 tall and heavy, — probably fourteen feet high, exceeding the Ostrich of 

 our day, and even the huge Moa of New Zealand (p. 580). If the tracks 

 of this animal are those of a Dinosaur, instead of a Bird, the height of 

 the biped Reptile could hardly have been less than that here stated. 



Smaller species were common, and many have been described. Fig. 



Fig. 729 



Slab of sandstone, with tracks of 

 Brontozoum giganteum ( X3^)- Birds and Reptiles (Xqtt). 



730 (from Hitchcock) represents a large slab, with its lines of tracks, 

 showing that a number of these three-toed animals (a, b, c) and at 

 least one Amphibian (d) passed over the muddy surface during the 

 same day, or before the tides or freshets made new depositions of de- 

 tritus : the tracks, a, a, are enlarged views of b, and still are only one 

 tenth of the natural size. 



Mammals. — The only Mammal thus far discovered in the Ameri- 

 can rocks was made known by Professor Emmons. The specimens 



Fig. 731. 



Dromatherium sylvestre. 



are two jaw-bones (Fig. 731), found in North Carolina. According 

 to Professor Owen, they belonged to an Insectivorous (insect-eating) 



