Ornithichnology. " 319 



even less than these impressions ; yet as the smaller ones might 

 have been made by the young of the larger birds, I shall regard them 

 only as varieties. 



Fig. 5, exhibits three tracks of O. tuherosus, on a flagging stone, 

 directly in front of the door of the Court House in Northampton. 

 The foot is eight inches long and the step thirty three inches ; the 

 longest I have noticed in this species. This stone was brought from 

 the quarry on the east side of Mount Tom. 



O. ingens. Three toed ; length of the foot, exclusive of the 

 hairy appendage, fifteen to sixteen inches. No claws visible in any 

 specimens that I have found. Toes much narrower than in O. gi- 

 ganteus, and tapering gradually to a point ; quite divaricate. The 

 best specimen that I possess, exhibits, at a few inches behind the 

 heel, a depression nearly an inch deep, and several inches across ; 

 the anterior slopes to which, in the rear, appears if large bristles had 

 been impressed upon the mud. I have been led to suspect that the 

 bird possessed a sort of knobbed heel, covered with wiry feathers, 

 which sunk into the mud when the track was deep. Yet I do not 

 feel very confident as to the nature of this appendage. The impres- 

 sion of the bristles extends backwards from the heel, at least eight 

 or nine inches ; so that the whole length of the track is not less than 

 two feet ! The length of the step appears to have been about six 

 feet ; although I have had but few opportuties to ascertain this fact. 



The rock on which this species of track appears, is composed of 

 a fine blue mud, such as is now common in ponds and estuaries ; and 

 where the bird trod upon it, in some cases, it seems that the mud 

 was crowded upwards, forming a ridge around the track in front, sev- 

 eral inches in height. Indeed, I hesitate not to say, that the impres- 

 sion made on the mud appears to have been almost as deep, indica- 

 ting a pressure almost as great, as if an Elephant had passed over it. 

 I could not persuade myself, until the evidence became perfectly 

 irresistible, that I was examining merely the track of a bird. 



O. ingens, a minor. Length of the foot, about twelve inches ; 

 step from forty two to forty five inches. In other respects, it cor- 

 responds with O. ingens : and although I was at first inclined to re- 

 gard it as a distinct species, I prefer upon the whole, to put it down 

 as a smaller variety of O. ingens. Fig 3, exhibits a series of tracks 

 of this variety, copied from the face of the rock in the quarry at the 

 Horse Race. The hairy appendage is scarcely visible on the rock 

 and is therefore, omitted in the figure. It is wanting, probably be- 



