ae 
of Fossil Footmarks. ; 279 
the drawings, compare with no created thing other than me 
footprints of birds. In rare instances even, the papillose im- 
pressions of the integuments are true to the very life. In 
pursuing the line of footsteps upon the rock, it is invariably 
composed of alternate feet, the long and short toes in their 
relative positions, and the middle one pointing out the place 
of the advanced opposite foot. "These unequivocal analogies 
therefore prove, what was self-evident, that no other known 
animal could have produced the impressions upon the sand- 
stone rocks. 
An inspection of the plates, it is believed, cannot fail to 
overwhelm all doubts as to the nature of these splendid fossils. 
Each represents a foot specifically distinct, yet the general 
resemblance is very striking. The toes in these examples are 
exceedingly massive: a provision adapted to resist the soft 
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bottoms traversed by the birds. Pl. XXIII. f. 1, is a fac-simile 
a Superb species found nowhere but at Turner’s Falls. Tt was 
à short-legged, heavy bird, as we know by the shortness of the 
as' compared with its size, by the zigzag direction of a 
Connecting the impressions, and by their depth even upon 
consolidated mud. Fig. 3, in the diagram, represents the 
comparative size of the foot with the stride, which was, in this 
instanee, 14 inches, and also the irregular direction from [step 
t The weight of this bird was such that the bottom of 
impress is moulded smooth as glass, and the toes sink so 
