File:The Quarterly journal of the Geological Society of London (12736581303).jpg

72G
rROF. W. BOYD DAWKINS ON TnE OSSIFEROUS DEPOSIT
ness of 21 feet, through the whole of which bones were scattered,
but in far greater quantity below than above. In one part the
remains of fox, wolf, bison, and reindeer were all matted together ;
and in another on the west side there was a stratum of bones, mostly
decayed, which measured 4x3x2 feet. On the west side also, close
under tho rocks, the bones were soldered into a compact breccia by
the infiltration of carbonate of lime. Close to this two perfect skulls
of bison lay crosswise, the one over the other. Ultimately the rock-
basin began to narrow, and the ossiferous clay to disappear ; we
traced it downwards until it rested on loose angular fragments of
limestone which filled a vertical shaft (fig. 1). We cleared it out on
every side except the north; and into that we tunnelled for 5 or 6 feet,
till further excavation became dangerous. The rock also reappearing
at the surface (figs. 2 & 3) showed that it did not extend far in that
direction, and rendered further work unnecessary.
Fig. 3,
■Ground-plan of Windy -Knoll Fissure.
(Scale 40 feet to 1 inch.)
4. The Koch-basin a Sivalloiv-Jwle. — It was obvious (see section
and plan, figs. 1 & 3) that tho bottom of the rock-basin ended in a
vertical shaft, and that it belonged to the class of " swallow -holes,"
" chaudrons du diable," or " katavothra," which are to be found in
most limestone regions, and which have been formed by the conver-
gence of water charged with carbonic acid on a point of weakness in
the rock offered by the intersection of two or more systems of joints.
In the immediate neighbourhood of Windy Knoll these swallow-holes
abound ; and through them the drainage of the upland valley to the
west passes into the series of caverns that underlies the limestone
ridges, averaging 1600 feet high, separating it from the valley of Hope
and Castlcton to the east. In the quarry close by, a cavern has been
discovered of very considerable size, in which one of these swallow-
holes may be studied from the underside. On descending through