328 Ornithichnology. 



marks. As to the larger species of Ornithichnites, however, we can 

 make no comparison with existing species ; because no birds now on 

 the globe have feet which approximate in size to O. giganteus and 

 ingens. One cannot but see, however, that birds which measured 

 from four to six feet at each step, must have had very long legs, and 

 were therefore waders. 



But the zoologist will object, that some of them appear to have 

 had their legs covered, even to the toes, if not with feathers, yet 

 with bristles ; while all the known Grallae have naked legs. This 

 is certainly a very strong presumptive evidence against their having 

 been waders in the literal sense, and perhaps it is an insuperable ob- 

 jection against ranking them among the Grallse at all. Yet I would 

 remark, in the first place, that it is not certain I understand the na- 

 ture of this pecuhar appendage to the heel, although I cannot ex- 

 plain it in any other way than I have done, and I do not see why 

 that is not satisfactory. Again, since we should expect a priori, 

 great peculiarities of structure in animals that inhabited the globe 

 so early, is it incredible that even the genuine wading birds of that 

 epoch might have had an appendage to their feet of filaments like 

 bristles ? We may not be able to see their use ; nor can we understand 

 that of the thoracic filaments attached to the genus Polynemus among 

 fishes ; nor to the byssus of the Pinna, among shells. Once more, 

 these Ornithichnites, with the appendage under consideration, might 

 have been produced by that portion of the Grallse denominated Cur- 

 sores by Temminck, and which might have frequented the shores of 

 lakes and estuaries for food. Between the genus Rhea of these 

 birds, and the O. ingens, there is one point of resemblance which I 

 ought perhaps to notice. The Rhea has a callous knob in the place of 

 a hind toe ; and in the O. ingens, a protuberance of that sort seems 

 to have left an impression. But finally, whatever we may think of the 

 radiating appendage, I think it quite certain, and in the sequel shall 

 endeavor to prove, that all the tracks which I have described must 

 have been made either beneath the waters of an estuary, lake, 

 pond, or river, or on their margin, where the waters would often 

 overflow the place. If so, the habits of all these ancients birds 

 must have corresponded to those of the modern Grallae. 



I have stated in the commencement of this paper, that the rock 

 on which these Ornithichnites are found, is the new red sandstone ; 

 or perhaps I ought to call it the equivalent of that group of rocks 

 in Europe ; that is, it seems to have been formed under similar cir- 

 cumstances, and probably at nearly the same geological epoch.. 



