130 AN ATTEMPT TO DESCRIBE THE ANIiMALS THAT MADE 



the earliest discovery of fossil footmarks, that I shall omit them 

 here ; especially as my object is to give my latest, rather than 

 my early, views of the subject. I shall, therefore, only mention 

 the successive developments which my views have undergone. 



The footmarks hitherto discovered in the United States out of 

 New England amount to two or three species only ; and although 

 I shall describe these in the present paper, yet all the important 

 characters on which I found my results are derived from those of 

 the valley of Connecticut River. 



The first account ever published of these footmarks was given in 

 the American Journal of Science for 1836, where I figured and 

 described seven species; that is, I supposed that these tracks were 

 made by seven different species of animals. And since I had no 

 evidence that all of them were not bipeds, and positive evidence 

 that most of them were, I named the tracks Ornithichnites ; but 

 left the animals themselves unnamed. Five years of further ex- 

 amination enabled me to swell this list to twenty-seven species ; 

 of which I gave a description, with drawings of the natural size, in 

 1841, in my Final Report on the Geology of Massachusetts, Up 

 to that time, however, I had no sure evidence that any of them 

 were made by quadrupeds. Yet a large proportion of them bore 

 such a strong resemblance to the tracks of saurian reptiles, that 1 

 denominated them Sauroidichnites ; intending, however, by the 

 term, merely to convey an intimation that they might prove to be 

 reptilian. To the other tracks I applied the name of Ornithoidich- 

 nites. In 1841, when, in the Transactions of the Association 

 of American Geologists, I gave an account of five more species 

 of tracks, I first ventured to describe one species as of decidedly 

 quadrupedal origin, namely, the Sauroidichnites Dewey i. In my 

 Report on Ichnolithology, made to the Association of American 



