Ornithichnology. 321 



gin of the stone. The length of the toes, exclusive of the hairy ap- 

 pendage, is about five inches. 



Fig. 16, is a very similar case to the last, except that the side 

 toes are scarcely visible ; probably because the layer of rock con- 

 taining them, was somewhat below the layer on which the bird ori- 

 ginally trod. The steps in the right hand row are twenty one inch- 

 es, and in the other, eighteen inches. From the Horse Race on 

 gray micaceous sandstone. 



Fig. 10, was sketched from a specimen in my possession, from 

 the Horse Race. The tracks are exhibited very distinctly in relief, 

 and also on the opposite side of the stone as depressions. There 

 are at least two varieties, as to size, of O. diversus ; and the tracks 

 are irregularly situated upon the stone. The length of the foot va- 

 ries from four to six inches. 



Fig. 23, represents a similar specimen from the same place, and 

 of the same species. The tracks are depressions, and most of them 

 very distinct. There are at least, three pairs of tracks connected 

 by dotted lines ; that is, they are the steps of birds moving in differ- 

 ent directions. The length of the step, varies from twelve to four- 

 teen inches. Six of the tracks are insulated ; that is, not connected 

 with others upon the specimen. The length of the foot in all the 

 tracks, except n, is four inches ; that of w, six inches. The rock is 

 fine gray micaceous sandstone. 



Fig. 24, shews another similar group of the same species and size 

 as in the last figure ; n being six inches long, and the other tracks 

 four inches. Three tracks on the lower part of the figure, and two 

 along the central part, are obviously the steps of birds moving in 

 different directions ; the shorter steps being twelve inches, and the 

 longer one eighteen inches. Four of the tracks, from the Horse Race 

 quarry, on gray micaceous sandstone, are insulated. 



/3 platydactylus. Middle toe from two to three inches long, 

 swelling out towards the extremity in an unusual manner. Hairy 

 appendage behind very large and distinct. Length of the step six 

 to eight inches. At the Horse Race; rather com.mon. The five 

 small tracks crossing Fig. 6 diagonally, belong to this variety ; a 

 sixth being wanting to complete the series. It differs from the va- 

 riety a clarus, chiefly in the swelling of the middle toe, and in its 

 diminutive size. 



Since the radiating lines behind the foot in O. ingens and O. di- 

 versus, are much fainter than the furrows made by the toes, we 



Vol. XXIX.— No, 2, 41 



