32 



R. L. Moodie — Vertebrate Footjprin\ 



cares to go. If it is a dinosaur it would seem to indicate that 

 the group arose in Carboniferous times. The three-toed con- 

 dition of the footprint, the elongate backward extension of the 

 heel all agree with the impressions the theropod dinosaurs left 

 in the Triassic sandstones of the Connecticut Valley. That 

 the impression was made by an amphibian of some kind is 

 possible, but we know at the present time no three-toed member 

 of that group. No parasuchian is known with an elongate heel 

 and none with only three toes such as the impression indicates. 

 That the impression was made by a bird is much more out of 



the question. At the time when these footprints were made 

 we knew of several groups of air-breathing vertebrates in 

 other portions of this continent and elsewhere. Aside from 

 the amphibians tL^re were the theromorph reptiles which 

 agreed very closely with the higher Amphibia in foot structure. 

 It will thus be seen that while the exact nature of the 

 impression is uncertain, no one can deny that it is a footprint 

 nor can it be denied that the impressions exhibit characters 

 which are those of the theropod dinosaurs. Future discoveries 

 may result in a further explanation of the nature of these 

 interesting impressions ; but again, this may remain as has 

 Eosaurus, Thinopus antiquus and other discoveries, the only 

 evidence we have of the existence, in the closing period of 



