184 Explorations in the Bone Cave of Ballynanuntra. 
feet deep, were also continued for twenty feet outside the present mouth of the 
eave, between the flanking walls of rock, which form continuations of the sides of 
the cave, and indicate that it formerly extended further out. That such an 
extension of the cave once existed is shown by a stalagmite floor with upright 
cones coating a bench of undisturbed gravel, (the continuation of No. 5) fourteen 
feet outside the present entrance, and more than four feet below the recent 
surface. This must have been formed by water dripping from a roof of rock that 
is now gone, and extended at least sixteen feet outside the point where a continuous 
roof now commences, so that objects found in the accumulations within these 
limits evidently belong to the true cave deposits. 
It has already been mentioned that the rocks in the vicinity of this and the 
neighbouring caves have a water-worn appearance. This is perceptible at from 
seventeen to twelve feet outside the cave’s mouth, on the left * side, a little below 
the datum level, where a bench of the limestone rock is remarkably smoothed 
and rounded ; while the left wall from the latter spot inwards exhibits a singular 
hollow curve, shown in cross sections A to E on Plate XI. The roof also for the 
first twenty-four feet. has an arched, worn appearance, its angles having been 
rounded off, and the walls in other places are similarly worn. These facts seem 
to prove, for reasons stated below, that the cave was originally shaped by water. 
The hollow curve in the left wall (which is best shown in cross-section B) ceases 
about 18 inches below the datum level. Similar hollows or grooves occur in the sides 
of Brixham cave, and these are supposed by Mr. Pengelly to have been worn by a 
stream, having a very limited vertical range, that flowed through it at a time when 
the lower part of that cave was filled with some accumulation capable of protecting 
the walls up to the level at which the hollow curves commenced. In corroboration 
of such a theory in the case of the present cave it may be mentioned that, on the 
left side from near the mouth to nine or ten feet outside it, a bench of gravel, more 
or less brecciated, lay undisturbed against the rocky wall, as shown in cross-section A. 
The top of this gravel-bed was nearly on a level with the bottom of the hollow curve 
in the rock, but did not cover any of the latter, and it may show the general level 
at which the gravel in this cave stood at one period. 
On the right side was a range of swallow holes, shown in cross-sections A and B. 
These were concealed by the upper strata, but at a greater depth were found to be 
empty. One of them, however, on being opened out was found at some depth to be 
choked with pebbles, blocks of brecciated gravel (fifth stratum) and broken pieces 
of stalagmite (fourth stratum) surrounded by pale sandy earth (third stratum) 
showing that the contents of the cave had a tendency to be carried down these 
swallow holes, which were very plainly enlarged and worn out of the rock by water 
and detritus. The smooth surface of another of them exhibits little buttons of 
calcareous matter such as are formed in cavern pools. The cave’s floor dips from 
* The terms “right” and “left” are hereafter used with reference to a person entering the cave. 
