8s 7 Dr, Duncan on the Foot-Marks of Animals 
deposited subsequently to the period in which the tracks were 
left on the surface of the sand. . 
7th, As far down as the quarry has yet been worked, which 
is not less than forty-five feet perpendicularly from the top 
of the rock, similar impressions have been found, and these 
equally distinct and well defined with such as are nearer the 
surface, 
8th, The impressions are not confined to a single stratum, 
but have been found on many successive strata. Since the 
foot-marks were first discovered, about forty yards of sand- 
stone have been removed in a direction perpendicular to the 
line of strata, and throughout the whole of that extent, im- 
pressions have, at frequently recurring intervals, been uncov- 
ered, particularly in one part of the quarry, and still contin- 
ue to be uncovered. 
_ Hence it must be inferred that the process, whatever it 
may have been, by which the impressions were buried in the 
sand, that of drifting by storms for instance, has not been oc- 
casioned by any sudden or isolated convulsion of nature but 
has been carried on through many successive years or rather 
ages. Nor has it been the result of tides on the shore of 
the sea, which can scarcely be supposed to have flowed to 
the height of between forty and fitty feet; and even if they 
done so, would certainly have swept away or filled up 
period of rainy 
ften and diffuse 
were to traverse a hill thus for uld be 
either altogether obliterated, or partially filled up, of which 
med, their tracks wo 
