ORIGIN AND CHARACTERISTICS 3 



reptiles are more closely related to each other 

 than either is to all remaining forms of vertebrate 

 life, nothing displaying nearer afBnities with birds 

 than those gigantic reptilian forms known as 

 Dinosaurs have yet been discovered. Casts of 

 footprints found upon the Triassic sandstone 

 in the valley of the Connecticut in New England 

 were long supposed to be those of birds, but 

 palaeontologists appear now to be generally 

 agreed that these impressions were made by the 

 feet of Dinosaurian reptiles. Some of these 

 footprints, measuring as many as seventeen 

 inches in length, indicate creatures of vast size 

 with a stride of about eight feet ! Dr. Hitchcock 

 enumerates the footprints of as many as twenty- 

 three species of what he termed Ornithichnites 

 — a Greek compound, signifying fossil footprints 

 of birds, and which of course in the light of 

 modern opinion now becomes obsolete. From 

 the Bunter Sandstein of the Triassic system to 

 the Solenhofen slate formation of the Jurassic 

 system constitutes a vast period of geological 

 time, and yet this separates these reputed Orni- 

 thichnites from the first really fossil bird respect- 

 ing the identity of which authorities are in no 

 doubt. This, the earliest known avine form, is 

 the Archaeopteryx (a second species has lately 



