■252 BifiDS. 



The evidence as to the ornithic character of the footprints 

 in the American Trias is as follows : — 



Firstly, The tracks appear to be certainly those of a hipped 

 — that is to say, of an animal which often, if not always, 



Fig. 585. — Footprint supposed to belong to a Bird. Tiiassie Sandstones of Connecticut. 



walked upon two legs. No living animals walk habitually 

 upon two legs except Man and Birds, and therefore there is 

 a lyrinid facie presumption that the authors of these prints 

 were birds. 



Secondly, The impressions are mostly tridactylous — that is 

 to say, formed by an animal with three toes on each foot, as 

 is the case in many Waders and most Cursorial Birds. 



Thirdly, The impressions of the toes show the same nu- 

 merical progression in the numlier of phalanges as exists in 

 living birds — that is to say, the innermost of the anterior 

 toes has three phalanges, the middle one has four, and the 

 outermost toe has five phalanges. 



Taking this evidence collectively, it would have seemed, 

 till lately, tolerably certain that these impressions w^ere 

 formed by Birds. In spite, however, of the general resem- 

 blance of these footprints to those of Birds, the balance of 

 evidence at the present moment is in favour of the view 

 that they are, in great part, and perhaps wholly, the work 

 of Reptiles. Some of the three-toed footprints have been 

 shown to be accompanied with the recognisable traces of the 



