416 R. S. Lull — Life of the Connecticut Trias. 



no feature to debar it from a more or less direct ancestry to 

 its American successors in time. 



The Vertebrate Footprints. 



The vertebrate tracks are so numerous and so varied withal 

 that the reader is referred to another extract of the Connecti- 

 cut valley memoir, to appear shortly, for the list with a brief 

 diagnosis of each of the several genera. 



They represent cursorial quadrupedal forms similar to Ste- 

 gomus, and dinosaurs both carnivorous and herbivorous as 

 well. Of the former some are very large, indicating animals 

 of at least 27 feet provided the proportions were those of Allo- 

 saurus, for instance, of the Morrison, while on the other hand 

 there are tracks of such extreme delicacy among the bipedal 

 group that the application of the term dinosaur or " terrible 

 lizard" to such as made them seems absurd. There are also 

 the trails of occasionally erect forms and of true quadrupeds, 

 some doubtless of lizard- or salamander-like shape, but all of 

 these are of small size as compared with the dinosaurian foot- 

 prints. 



Geologically the first known footprints are reported from 

 the anterior shales and are all apparently referable to carnivor- 

 ous dinosaurs. The posterior shales are of interest in that here 

 are found the first plant-feeding dinosaur tracks in the Newark 

 rocks. It is not until the upper series of sandstones and shales 

 is reached that the great profusion of tracks is manifest, not 

 that the animals were necessarily any more numerous, but that 

 the acme in the perfection of track preservation for which this 

 region is so noted was reached. 



In all the total number of footprint genera is 43 while the 

 species exceed this, there being no fewer than 98 all told. 



Resume. 



The story of the Connecticut valley, as the evidence at hand 

 now reveals it, may be summarized as follows : 



Far back in the remote Triassic period, when the Age of 

 Reptiles was yet young, there were laid down in a gradually 

 deepening trough in the older rocks the great accumulations 

 of gravels, sands, and clays, interbedded with vast lava sheets, 

 which constitute the sediments of the Newark system. The 

 older notions of the submarine or estuarine origin of these 

 rocks have been abandoned on the ground of their containing no 

 relics whatever of marine or even brackish water origin, and 

 of the difficulty of accounting for the deposition of the sedi- 

 ments except by tidal currents of far greater transporting 

 power and governed by laws of movement at variance with 



