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foot of the African ostrich; being a long thick toe, 
with a shorter one, not unlike a thumb, on the side. 
An impression approximating this, but of small size, 
may be seen on the slab of the Anomeepus Scambus. 
The formation of bird-tracks is well represented by 
a clay specimen, about an inch thick, and ten inches 
long. ‘This is a piece of dried clay, obtained by Presi- 
dent Hitchcock from the banks of the Connecticut, 
and produced by washings from clay on the shore 
above, covered with foot-impressions of a small tridac- 
tylous bird, and dried in the sun. This piece shows, 
in a way not to be questioned, the manner in which 
the ancient vestiges were produced. Sir Charles Lyell 
noticed a similar fact on the banks of the Bay of 
Fundy. 
