pi 
chusetts to Middletown in Connecticut, a distance of 
about eighty miles. 
A slab from Turner’s Falls, obtained for me by Dr. 
Deane in 1845, measuring two feet by two and a half, 
and two inches in thickness, contains at least ten 
different sets of impressions, varying from five inches 
in length to two and a half, with a proportionate 
length of stride from thirteen inches to six. All these 
are tridactylous, and represent at least four different 
species. In most of them the distinction of articula- 
tion is quite clear. The articulations of each toe can 
readily be counted, and they are found to agree with 
the general statement made above as to number. The 
impressions are singularly varied as to depth; some of 
them, perfectly distinct, are superficial, like those 
made by the fingers laid lightly on a mass of dough, 
while others are of sufficient depth nearly to bury the 
toes ; some of the tracks cross each other, and, being 
of different sizes, belong to animals of different ages 
or different species. ‘There is one curious instance of 
the tracks of a large and heavy bird, in which, from 
the softness of the mud, the bird slipped in a lateral 
direction, and then gained a firm footing; the mark of 
the first step, though deep, is ill-defined and uncertain; 
the space intervening between the tracks is super- 
ficially furrowed; in the settled step, which is the 
° 
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