yey se Sa 
ee ee ieee ey ee eS ee ee ON ee PS 
~ 
E.. Hitchcock on Fossil Footmarks of the Connecticut Valley. 55 
trace of them, as is the case with every other species of Lithich- 
nozoa. They had but three toes: at least, if a fourth existed 
in any case, it must have been articulated so ‘high as not to reach 
the ground. These three toes are articulated to a tarso-metatar- 
sus, as is the case with nearly all tridactyle animals. They had 
the same number of phalanges as the birds. 
e impressions left by the cushion beneath those processes 
of the tarso-metatarsus which form the heel correspond to those 
which living birds would make, and, so far as I have examined, 
not to those of any other class of animals, though my examina- 
tions on this point have been few. The claws and papille agree 
essentially with those of birds. Finally, the great length of 
stride in some cases, and the position of the tracks nearly on a 
ies line, sera long legs of wading birds, and not any other 
ind of a 
Most of me arguments are good for the ornithic origin of 
these tracks, whatever opinion we may entertain as to the Ano- 
moepus. The only difference is, that, if we regard it as a reptile, 
the argument from the number ‘of phalanges must be given up; 
if as a bird, that strong evidence is retained. But even without 
this, I cannot hesitate to reckon the biped thick-toed Lithiehno- 
zoa as birds; for I see no characters in their tracks that ally 
them to any other animals. I must consider them not only as 
birds, but as forming a quite perfect type of birds for sandstone 
days. The analogies taught us by paleontology (see Prof. Dana’s 
appended letter) would lead us to expect also in the same peri 
a lower group of birds, and these may have been the Archxop- 
nye and perhaps the Anomcepus, with some other genera of 
Sag which I might name, 
How then could I avoid the conelusion that these animals 
were birds? Doubtless with some peculiarities of structure, 
brin ve them into the “ comprehensive types of Daa but still 
ever maintain the avian’ character of dies animals. It is cer- 
tainly gratifying even isd seem to touch soundings, after having 
e sea of difficulty, and I cannot but 
hope that subsequent paseaahies will show that we have not cast 
anchor ey in quicksand. 
tews.— Having occasion while engaged in the 
investigations ‘Setalled | in the preceding paper to write a letter on 
business to Prof. J. D. Dana, [ mentioned some of the results to 
* A new and much needed word used by Professor Richard Owen ina recent 
venture to introduce into print. 
’ letter, and which I 
