E.. Hitchcock on new Fossil Footmarks, 99 
But the unmistakable evidence of a tail is the most remarka- 
ble thing about this animal. It cannot be doubted, I think, by 
any one who will look at the slab, and it leads one at once to 
look sharply for marks of its quadrupedal character. But no 
trace of more than two feet is to be found, although the exist- 
ence of so many small tracks on the slab shows that the rock is 
| a fine one for retaining the marks of the fore feet if they had 
| existed. The only supposition making its quadrupedal charac- 
ter at all plausible, is, that the fore feet might have made an im- 
. pression not quite so deep as the hind ones, and the layer con- 
taining them, may have been scaled off without our noticing their 
h existence. J saw the tracks before they were fully uncovered, and 
observed no signs of fore feet; and Mr. Field has had great expe- 
rience in such matters, so that had they existed, I think he must 
have seen them. ee 
Upon the whole, the evidence is very strong that this animal 
Was an enormous biped with a very long tail! I say a long tail ; 
for when the tracks of a biped follow one another almost in a 
straight line, the animal must have had long legs. hree of 
| these tracks are almost exactly inaline. At the fourth step it 
trod a little to the right, which swayed the body and consequently 
| the tail, somewhat in that direction. 
The inquiry naturally arises, whether these facts do not weak- 
| 
| 
: 
; 
en very much the proof that any of the tracks in the sandstone 
of the Connecticut valley were made by birds. For here we 
have no time to follow out this thought. : 
_ But whatever opinion we may form as to the place in a scien- 
tific arrangement occupied by these animals, all must be struc 
With their extraordinary ‘size and peculiarities. It is amazing 
how different were the former from the present occupants of 
