Dr. Deane’s Letter to Dr. Mantell. 179 
state of Massachusetts. Both gentlemen admitted the plausibil- 
ity of my statements, yet remained incredulous as to inferences, 
ascribing the origin of these remains to accidental causes, and it 
was only after accurate models were transmitted to them, that 
the real truth was obvious. Prof. H. then gave the specimens | 
an inspection which resulted in the unqualified conviction that 
these foot-prints were genuine vestiges of birds. He subsequently 
explored the entire valley of the Connecticut River with extra- 
ordinary success, the details of which he has given to the scien- 
tific world in several treatises of great ability. 
During the past year I have received letters from Prof. Silliman, 
enquiring if I could furnish such examples of these fossils, as 
might appear to establish the fact that they were unquestionable 
footsteps of birds, but it is only at this time in my power to render 
a satisfactory reply, and that reply is most emphatically expressed 
by the beautiful specimens I now have the pleasure of sending you. 
You cannot fail to observe, notwithstanding the enormous con- 
trast in the size of these footmarks, the striking resemblance they 
bear to each other, and for distinctness and beauty of impression, 
and fidelity to living nature, the O. twberosus is most remarkable 
of all, indeed its perfection supplies a model for the compara- 
tive anatomist. Although the distinct varieties of these imprints 
hitherto discovered, established several intrinsic characters com- 
mon to all, such as succession of feet, numbers and arrangements 
of toes, form and insertion of claws, &c., it was not until the 
discovery of this variety that an example occurred so faultless as 
to illustrate the construction of the joints with precise accuracy, 
although Prof. Hitchcock had long suspected the truth that its 
perfection reveals. In exploring the bed of the river at low wa- 
ter in 1841, I was gratified with the discovery of several new 
species of these imprints, exquisitely perfect. If they had been 
made in wax and turned into solid stone, they could not have 
been more so. The material upon which the animal trod pos- 
sessed a degree of tenacity not only to retain distinctly the lobate 
form of the respective joints, but even in some rare instances, 
the corrugations of the integuments. In them every feature of 
the impression is without blemish, the ridges marking the boun- 
daries of the joints and also of the toes being clear, sharp and 
correctly defined, and the impress vividly distinct. 'These fea- 
tures are all displayed by examples now before you. The sur- 
face of the rock is compact and smooth, and I wish to call your 
