Ornithichnology. 325 



to the right, (scarcely visible in the drawing,) corresponding exactly 

 to the step of a bird, but not to that of a quadruped. The thumb, 

 or short toe, also, is on opposite sides in the two tracks, proving the 

 animal that made them to have been a biped ; for had they been 

 produced by the two right or the two left feet of a quadruped, the 

 short toe would have been on the same side in both tracks. 



I am aware, that these impressions do not correspond to the foot 

 of any existing bird ; at least, I cannot find any one of this descrip- 

 tion in the ornithological works within my reach. Four toed birds 

 are, indeed, the most common, but in no instance do they all point 

 forward.* Yet, since peculiarities of structure occur in most other 

 animals, found petrified deep in the secondary rocks, ought we to be 

 surprised to find them in the birds of early times ? And can any 

 one suppose, that the slight addition of a short inner toe, ought to 

 exclude the animal, when the proof of its being a biped Is so clear, 

 from the class of birds ? 



O. minimus. Three toed ; destitute of a hairy heel ; foot from 

 half an inch to an inch and a half long ; toes spreading widely ; 

 nearly of equal length ; step three to five inches ; quite common 

 at the Horse Race. Generally, the foot is rather over an inch long, 

 but one very distinct specimen is only half an inch. 

 _ Fig. 9 exhibits a succession of tracks of this species, four inches 

 apart, found at the Horse Race. 



It will probably be suggested, as I have already intimated in one 

 case, that all the smaller tracks were made by the young of the larger 

 species of birds ; and although I doubt very much whether this is 

 the fact to any great extent, yet it will be seen, that I have regarded 

 no track as a distinct species, that does not differ from the others, by 

 some other peculiarity than the size, except perhaps O. ingens and 

 O. ditiersus, about which I have already remarked. And besides 

 the peculiarities that have been named, there are others, which will 

 be obvious to a practiced eye, but which it is not easy to express in 

 language. 



Naturalists may perhaps doubt as to the nature of the appendage 

 that produced the radiating impression in some of the species that 

 have been described. Yet it is well known that some species of 

 living birds have the tarsus very low down covered with hair like 



* In some drawings of the feet of the genus Paradisea, especially that in Rees' 

 Cyclopedia, it would seem as if all the toes were directed forward; but ornitholo- 

 gists inform us, that this is not the case. See Dictionnaire Classique d'Histoire 

 Naturelle, Art. Paradisea. 



