224 AN ATTEMPT TO DESCRIBE THE ANIMALS THAT MADE 



by the animal when at rest upon all its feet, and certainlj look 

 like the imprints of a frog, scarcely less than a foot in diameter ; 

 or, possibly, a tortoise. 



In order to show how great changes of tracks frequently occur 

 on layers of rock only an inch apart, I have given, on Plate 21, 

 fig. 2, the under side of the above slab, belonging to Mr. Leonard. 

 Scarcely one of these tracks corresponds to those upon the upper 

 side of the slab. Only one example of a track of Anomcepus oc- 

 curs, though some of the other trifid feet may be the toes of the 

 hind foot of that animal. We see, also, three tracks of what is 

 probably the Ornithopus gallinaceus. 



Plate 20, fig. 3, is copied from a slab in Mr. Marsh's collection, 

 reduced to one third of its natural size. It seems to show a suc- 

 cession of the tracks of Anomcepus scambus, the last four very 

 similar to those upon Plate 21, fig. 1 ; that is, they seem to have 

 been made by the animal when sitting upon its haunches. Yet 

 the left-hand hind track is greatly injured by another track of an 

 animal moving in an opposite direction ; and the three fragments 

 of toes near it look like the fore feet of the Anomcepus. If so, the 

 heel of the hind feet did not reach the surface. 



Plate 20, fig. 9, is a sketch, reduced three times, from a small 

 slab presented me by Dr. Deane. It exhibits several tracks, more 

 or less perfect, very similar to those of the slabs above described. 

 In two cases, at least, on this slab, we seem to have little else but 

 the impression of the heel, with a part of the lower leg (a and b). 

 Yet a little in advance of a, we have impressions (c), indistinct I 

 admit, of a sort that reminded me of the feet of certain batrachi- 

 ans ; for example, the Anolis Edivardsii, of whose feet I have 

 given a sketch on Plate 20, fig. 7, copied from Griffith's Cuvier, 

 Vol. IX. p. 228. Yet I am by no means confident that I rightly 



