184 CAVES AND CAVE DEPOSITS. 
thinned off against the rock a little further east, as shown in the 
diagram, fig. 3. The core of the principal swallow-hole has, of 
Fig. 3.—Diagram-section, showing the looping-down of the deposits 
into the swallow-hole before the Section was cut back as far as 
represented in fig. 2. Index as in fig. 2. (Scale about 11 ft. 
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course Jong gone; it was where the earth fell in in the winter 
of 1886 (see fig. 3), just over where, according to my view, the 
water soaked first through the jointed, fissured, and funnelled 
rock into the cave, as it did afterwards througn the great 
angular masses of limestone derived from the breaking down 
of the wall and roof of the cave. Some of the superficial 
deposit was of so late a date that the marks of plough and 
harrow were found on the included stones. 
The cave had been filled in the usual way with material from 
superficial deposits washed in through openings, or from the 
decay of the rock, or carried in by beasts. The sand that 
occurred all along it was such as would be derived from the 
running sand of the drift outside, which is still being carried 
in in wet weather. 
The estuary of the Conway offers the most nearly similar con- 
ditions to those which must have prevailed in the estuary of the 
Clwyd during the submergence : if we could imagine the whole 
of the Vale of Clwyd submerged to a depth of some 400 feet ; 
cliffs of ancient drift being wasted in one place, and the solid 
rock touched in another; here banks thrown up which divert 
the currents, and clay and sand and gravel alternating. Frag- 
mentary shells in exactly the same condition, the same part pre- 
served, and most of them of the very same species as those in 
the Vale of Clwyd, occur in the shore-deposits of Deganwy. 
But wander on to where the sea rises and falls across the terraced 
rock, and stand there while the waves are moved by even such a 
breeze as would just let you sail a boat, and judge whether any 
loose subaérial deposit could remain 
