1822.] Rev. Mr. Buckland’s Account of Fossil Teeth, &c. 173 
ArTICLE V. 
Account of an Assemblage of Fossil Teeth and Bones, of Elephant, 
Rhinoceros, Hippopotamus, Bear, Tiger, and Hyena, and 16 
other Animals ; discovered in a Cave at Kirkdale, Yorkshire, 
in the Year 1821: with a Comparative View of five similar 
Caverns in various Parts of England, and others on the Contz- 
nent. By the Rev. William Buckland, FRS. FLS. Vice-Pre- 
sident of the Geological Society of London, and Professor of 
Mineralogy and Geology in the University of Oxford, &c. 
(Concluded from p- 145.) 
In many of the most highly preserved bones and teeth, there 
is a curious circumstance which, before I visited Kirkdale, had 
convinced me of the existence of the den, viz. a partial polish and 
wearing away to a considerable depth of one,side only; many 
straight fragments of the larger bones have one entire side, or 
the fractured edges of one side rubbed down and worn completely 
smooth, while the opposite side and ends of the same bone are 
sharp and untouched ; in the same manner as the upper portions 
of pitching stones in the street become rounded and polished, 
while their lower parts retain the exact form and angles which 
they possessed when first laid down. This can only be explained 
by referring the partial destruction of the solid bone to friction 
fiom the continual treading of the hyenas, and rubbing of their 
skin on the side that lay uppermost in the bottom of the den. 
In many of the smaller and curved bones also, particularly in 
those of the lower jaw, the convex surface only is uniformly that 
which has been worn down and polished, while the ends and 
concave surface have suffered no kind of change or destruction ; 
and this also admits of a similar explanation ; for the curvature 
of the bone would allow it to rest steady under constant treading 
only in this position; as long as the concave surface was upper- 
most, pressure on either extremity would cause it to tilt over and 
throw the convex side upwards ; and this done, the next pres- 
sure would cause its two extremities to sink into any soft sub- 
stance that lay beneath, and give it a steady and fixed position. 
Such seems to have been the process by which the curved frag- 
ments I allude to have not only received a partial polish on the 
convex side only, but have been submitted to so much friction, 
that in several instances more than one-fourth of the entire 
thickness of the bone, and a proportionate quantity of the outer 
side of the fangs and body of the teeth have been entirely worn 
away. I can imagine no other means than the repeated touch 
of the living hyenas’ feet and skin, by which this partial wearing 
