38 ICHNOGRAPHS OF THE 



PLATE VIII. 



Figs. 1 and 2. The same as described by Dr. Deane, and published in the Memoirs 

 of the American Academy, vol. 4, New Series. He there says : 



These represent a magnificent species of footprint, which I have selected 

 to illustrate the probability that certain analogous impressions, differing in magni- 

 tude, are due to an identical species, being impressed by individuals in various 

 stages of development. The distinctive marks of organization are very striking. 

 The foot is long, narrow, and distinctly impressed. A peculiar mark of distinction 

 in this species is the shortness of the outer toe, projecting backward and forward 

 little more than the inner toe. Another remarkable distinction is the circum- 

 stance that the lateral toes embrace and modify the form of the first joint of 

 the central toe. The latter toes diverge less than in other species. The tarsus 

 is invariably impressed, and its lobes and those of the respective joints are 

 exceedingly massive. The nails are perfectly defined. Those terminating the 

 lateral toes have an unusual divergence. The step is very long, in the figures 

 being about two feet. The bird was, doubtless, of great relative magnitude, for 

 the impress is always perfect, a circumstance resulting from condensation by great 

 pressure. These large and powerful birds appear to have outlived other species, 

 for, while those became extinct, or at least disappear, these are found under all 

 circumstances. They abound at Turner's Falls where the strata rest upon igne- 

 ous rock, and also at the Race, several miles distant, and at intermediate places. 



This description should be read having in mind the fact that Dr. Deane, when he 

 wrote it, considered many of the forms presented in the next succeeding eleven plates, as 

 well as those of the one under notice, as impressions of one species, in various stages 

 of growth. That his views in this respect were somewhat modified by subsequent obser- 

 vation, may be judged from the descriptions since given by him of Plates 13 and 15, 

 which follow. It is due to Dr. Deane to state that he did not at any time regard the 

 size alone of an imprint as generally of much value in determining specific character. 



The variety of form presented by this plate has been described by Dr. Hitchcock as 

 the footprint of the Gr alia tor cuneatus. This species had a step of from twenty-two to 

 twenty-four inches. Width of trackway, three and one half inches. 



