56 Two New Species of Fossil Footmarks. 
stratum, seems to have adapted itself to every irregularity, and 
now presents us with perfect casts of the original tracks, while the 
subjacent rock, which seems to have been a good moulding sand, 
does not hold together enough to show a single entire track. 
It seems that the rows of tracks at this locality were parallel 
to the edges of the water. They run nearly east and west, and 
in the direction of the strike of the strata; and in one or two — 
places upon the slab figured above, we can see where the water 
acted by gentle undulations upon the fine micaceous sand, an 
upon the coarse grit, partially wearing them both away, or inter- 
mixing them; and some of the large tracks look as if the san 
had been so wet that the impressions were partly filled up by 
the sand sliding into them. Only the second track exhibits the 
outlines of the parts entire. On that, the protuberances rise from 
one to two inches above the general surface. 'The extremities 
of this track have been broken off accidentally, except the inner 
one which is obscured by lying too near the edge of the water. 
It is obvious however how far it extended. As I have before 
mentioned, the second large track on fig. 1, forms the type by 
w 
at their extremities; and in ge , the sides converge rapidly 
on the last phalanx, so that if claws existed on the foot I 
think they did—they must have been short and blunt. 
Circumstances under which the tracks of these animals were 
made.—Have we any facts in this case indicating the cireum- 
stances under which these tracks were made and preserved? It 
is difficult, without a sketch of the topography of the region, to 
convey an adequate idea of their situation. The spot is on the 
south side of Mount Holyoke, which here runs nearly east 
west. It curves southerly, however, as it crosses the river, and 
on the west we have Mount Tom, as the continuation of Hol- 
yoke is called. On the east we have a primary range at 
