TRIASSIC PERIOD. 425 



appear to have been made by Batrachians or Labyrinthodonts. 

 While the smallest tracks indicate species of diminutive size as com- 

 pared with a modern frog, the largest must have been of enormous 

 dimensions. Professor Hitchcock calls the most gigantic of these 

 species Otozoum Moodii. The animal had a stride of three feet, and 

 appears to have walked like a biped, only occasionally bringing his 

 fore feet to the ground, as impressions of the latter are not often 

 distinct. Fig. 644 is the fore foot of this species, much reduced 

 (twenty inches being its full length), and 644 a the hind foot: their 

 relative sizes are here retained. One of the specimens of this spe- 

 cies in the Amherst Cabinet is a slab thirty feet long, containing 

 eleven tracks. 



In some species the impressions of the hind feet have but three 

 toes and resemble the tracks of birds. This is seen in fig. 641 a 

 (Anomcepus scambus Hk.). 



The print of the fore foot of the same animal is four-toed, as 

 shown in fig. 641. These figures are one-sixth the natural size. It 

 is remarkable that the toes of the hind feet have two, three, and 

 four phalanges successively, like the toes of birds, — a peculiarity 

 now unknown among Reptiles, but which characterized afterwards 

 the Iguanodon, the giant Reptile of the Wealden. 



Professor Hitchcock has described over fifty species of Reptiles 

 from the tracks found in the sandstone of the Connecticut valley. 



The evidence with regard to the existence of Birds at this period 

 has been shaken somewhat by the discovery of the three-toed rep- 

 tile-tracks ; and it is not impossible, as was early suspected, that 

 all the supposed bird-tracks may turn out to be Reptilian. Still, 

 this does not appear probable. 



The largest of the bird-tracks was of gigantic size, like the 

 largest of those of the Reptiles. Fig. 649 shows the form. It 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. Smaller species were common, 

 and many of them have been described. Fig. 649 A (from Hitch- 

 cock) represents a large slab, with its lines of tracks, showing 

 that a number of birds (a, b, c) and batrachians (d) passed along 

 over the muddy surface during the same day, or before the 

 tides or freshets made new depositions of detritus : the tracks 

 a, a, are enlarged views of b, and still are only one-tenth of the 

 natural size. The birds of the period appear to have been either 

 long-legged waders, or species of the Ostrich type. None were 

 web-footed. 



