236 REPORT ON THE DENEHOLE EXPLORATION
the tunnels. We found the upper part of the mound was composed
almost wholly of Thanet Sand with occasional pebbles, the lower
consisting of gravel with a slight admixture of sand. The gravel
formed a low cone, extending to the very ends of the chambers, the
sand a much steeper cone of much smaller horizontal extent.
Occasionally, lumps of chalk, the result of its weathering towards
the base of the shaft, appeared here and there. Estimating the
height of the mound below the centre of the shaft at 13 ft., we
found that the upper 7 or 8 ft. were Thanet Sand with occasional
pebbles, the lower 4 or 5 ft. gravel with a little sand. The concus-
sions, resulting from persons ascending and descending, caused the
mound to fall forward and fill up our trench, and we then obtained
the assistance of additional workmen in order to remove the mound,
the material being thrown into the lateral chambers, and the space
below the shaft entirely cleared. We found that as we got nearer the
floor the lumps of chalk, became much more numerous, and that
close to the shaft were great numbers of large flints, frequently more
or less squared. There can be little doubt that these large flints
had once been used for "steining" or lining the uppermost 6 or 8
feet of the shaft sunk through the surface gravel, which would be a
most treacherous and dangerous material around the mouth of a
shaft if unprotected by steining. And it is not unlikely that much
of the chalk, so specially abundant close to the floor, had been used
for the same purpose, courses of chalk having been found alternating
with others of brick in the shaft at Eltham Park, already mentioned.
The history of the mound we had been examining had apparently
been this. On the abandonment of the pit many centuries ago the
"steining" at the surface had given way here and there, and, not
having been repaired, this neglect had resulted in the total destruction
of the "steining" in a comparatively brief period. The large flints
and chalk lumps being the first material to fall, had no cone to roll
down, and mostly remained on the floor at a short distance from the
shaft. Then the gravel was rapidly denuded backwards till a slope
was attained on which plants could grow, when the waste of the
gravel gradually diminished till it almost entirely ceased. Lastly, we
had above the gravel the Thanet Sand, the falling of which from the
sides of the shaft appeared to have been the slow work of centuries.
Nothing whatever in the section of the mound suggested that any
influence but that of the weather had been concerned in its formation,
except that now and then animals of various kinds had been thrown