OF FOSSIL FOOTMARKS. 261 



SO nearly agreeing with those of birds. While, then, it seems to 

 me nnphilosophical, in the face of all living analogies, to assert 

 in respect to many of the tracks on stone, that they are not those 

 of birds ; it would be contrary to the cautious spirit of science on 

 the other hand, to decide that they are certainly such. I have 

 endeavored to take a middle course, by naming in my Final 

 Report, some of these tracks, OniUhoidic/inifes, or tracks resem- 

 bling' those of birds, and others, Sauroidichnites, or tracks resem- 

 bling' those of Saurians. Living analogies lead us to conclude 

 that most of them are the tracks of birds : but there is plausibility 

 enough in the opposite conjecture, to justify the use of terms that 

 imply resemblance rather than actual identity. 



New Species of Sauroidichnites. 



I dedicate this species to my esteemed friend, Rev. Chester 

 Dewey, of Rochester, New York; whose " Cai'icography " alone 

 would entitle him to such a notice, were it necessary to select a 

 single production from the labors of a whole life devoted to 

 science. 



Sauroidichnites Deiveyi. Toes four, all directed forward : the inner 

 toe, or thumb, very short : the three outer toes lying nearly parallel ; 

 all of them thick, and having claws more or less distinct : the outer 

 ones spreading only ten degrees. Impression made by the claws 

 deeper than any other part of the foot. Alternate tracks smaller. 

 Length of the largest track one and a quarter inch : of the smaller, 

 three quarters of an inch. Length of the step, three and a half 

 inches. Shown of the natural size on PI. XI, f. 9, copied from the only 

 specimen I have seen. 



It will be seen that the specimen shown on Fig. 9, bears a 

 stronger resemblance to the tracks of the Cheirotherium of Europe, 

 than any example which I have ever found in this country. The 

 specimen is so small, that we cannot, indeed, be sure that the 

 larger and smaller tracks succeed one another alternately ; espe- 

 cially as the larger ones point in directions so diverse. Yet I 

 incline to the opinion that the animal changed its course at this 

 point, and that the tracks are indeed in succession. This is ren- 

 dered more probable by the occurrence of a larger and smaller 



