Ornith ichnologij. 313 



zontalj or nearly so ; a conclusion, to which the geologist would 

 come, from evidence independent of the impressions. 



I have stated, that often tlie tracks can be traced in regular suc- 

 cession: but this is by no means always the case. Sometimes dif- 

 ferent species of animals, and different individuals, have crossed one 

 another's tracks so often, that all is confusion ; and the whole sur- 

 face appears to have been trodden over ; as we often see to be the 

 case, where quadrupeds, or ducks and geese resort, upon the muddy 

 shores of a stream or pond. Fig. 10 exhibits a case of this kind on 

 a specimen of sandstone in my possession from the Horse Race. 



I trust I have proceeded far enough in these details, to justify me 

 in coming to the conclusion, that these impressions are the tracks of 

 birds, made while the incipient sandstone and shale were in a plastic 

 state. This is the conclusion, to which the most common observer 

 comes, at once, upon inspecting the specimens. But the geologist 

 should be the last of all men to trust to first impressions. I shall, 

 therefore, briefly state the arguments that sustain this conclusion. 



1. These impressions are evidently the tracks of a biped animal. 

 For I have not been able to find an instance, where more than a sin- 

 gle row of impressions exists. 



2. They could not have been made by any other known biped, 

 except birds. On this point, I am happy to have the opinion of 



OTII 



3. They correspond very well with the tracks of birds. They 

 have the same ternary division of their anterior part, as the feet of 

 birds. Frequently, and perhaps always, the toes, like those of birds, 

 are terminated by claws. If the toes are sometimes slender and 

 sometimes thick and blunt, so are those of birds. If they are most- 

 ly wanting in the hind toe, so are many genera of birds, especially 



the Grallce. 



I am not aware that the tracks of living birds have been much no- 

 ticed ; and I regret that it has not been in my power to make more 

 observations of'^this sort, than I have done. But so far as I have 

 examined them, they bear a striking resemblance to the impressions 

 under consideration. I was particularly struck with the resemblance 

 at two of the quarries, that have been described ; viz. at the back 

 side of Mount Tom, and at the Horse Race. The rock at these 

 places, passes under the river, whose waters have deposited a thm 

 stratum of mud, just at the margin of the stream. Here in the sum- 

 mer, a few small species of Grails, particularly the snipes, resort for 



Vol. XXIX.— No. 2. 40 



