322 Ornithichnology. 



might expect, that by the deposition of new matter, when the rock 

 was forming, these hnes would sooner be obhterated. And such I 

 find to be the fact ; for I have sometimes taken a specimen, which, 

 although quite distinct, exhibited no traces of a hairy appendage, 

 and by carefully cleaving off successive layers of the rock, have 

 come at length to a layer that exhibited it. Hence, I have learned 

 to refer a specimen to O. diversus, which was destitute of a hairy 

 appendage, if in other respects it corresponded to that species. So 

 that, for the most part, the examples of continued tracks of that spe- 

 cies given in the drawings, are represented as destitute of this scopi- 

 form appearance ; because, in fact, they do not exhibit it on the rock. 



Fig. 4 was sketched from a flagging stone, brought from the east 

 side of Mount Tom, and lying on the side walk in front of the north 

 door of the first parish church in Northampton. The tracks, al- 

 though a good deal worn, are yet remarkably well characterized. 

 The right and left feet are very distinct ; and the toes have almost 

 exactly the same divergence in each track. The foot is six inches 

 long, and the toes are much nearer to equahty, as to length, than in 

 O. diversus, a clarus ; so that I have been almost disposed to re- 

 gard these tracks as a distinct species. But I supposed it most safe 

 to refer them to O. diversus. The length of the ^tep is twenty one 

 inches. 



Fig. 6 has been already referred to. The toes of the two prin- 

 cipal rows of tracks are shorter and more divaricate than is usual in 

 O. diversus, a clarus ; and no marks of a hairy appendage are pres- 

 ent, yet I rank them under that species. The length of the foot is 

 four inches, and the average length of the step twelve inches, vary- 

 ing from that not more than two or three inches. On the left is the 

 commencement of another similar row of tracks, of the same spe- 

 cies, and one insulated track. I found this example in the quarry 

 at the Horse Race ; and by enlarging the sketch, I might have 

 brought into view many other tracks. But none of them would 

 have exhibited so many steps in succession, as are shown in the pres- 

 ent drawing. 



Fig. 7 was sketched from a specimen about three feet long, in the 

 possession of Dr. Dwight of South Hadley. He obtained it, twenty 

 years ago, from a farmer in the north part of that town, who had 

 used it as a step stone, before the door of his house, and it was found 

 in the vicinity. It is a coarse gritstone, much coarser than any other 

 rock on which I have found these impressions. The foot is between 

 three and four inches long, and has no hairy appendage. Length 



