2i8 
NATURE NOTES 
Saturday, September 28. — A party of eleven arrived at Wrotham Station at 
2.35, with Mr. Kenneth W. Mumford as guide. The first section seen was 
that in the sand pit just opposite the main entrance to the station, and consisted 
of a drift deposit of sand, resting on the north flank of a slope of the Folkestone 
Beds. The first point noticed was the great amount of denudation that had 
taken place to form the Chalk escarpment, then plainly seen about two miles 
away in a northern direction. The causes of that immense denudation could 
not, the guide said, have been of any ordinary simple nature. This Plateau Drift 
is now only found in small isolated patches in different parts of Kent, Surrey 
and Sussex, but must once have been a very widely distributed one which had 
vanished with the departure of the crest of the Wealdom dome. The guide 
then led the way to the celebrated ossiferous fissures in the valley of the 
Shode, which have furnished us with more material for the reconstruction of 
the history of our island during the Tertiary Period than any other caves or 
fissures in the world. The theory Mr. Mumford advanced to account for the 
present condition of these faults was that a great downthrow has occurred 
approximately from Plaxtolin in a north-west direction to Holy Hill, amounting 
at that village to over five hundred feet. To this depression the clays lent 
themselves by forward progression at right angles to the line of depression, 
by which the outcrop of the Gault in the area under consideration is nearly 
doubled ; the limestones of the Hythe beds, being unable to bend, naturally 
fissured, so that we have a district permeated with cracks ot all sizes at right 
angles to the line of the downthrow. Some of these fissures become filled with 
surface-derived material, and thus remain without a sign of a fossil, and others 
remaining quite empty until a stream of later date being situated in a favourable 
position, as the Shode was, the waters gaining free access to them, carry into 
them their usual burdens and there deposit them. Sometimes the height to 
which the fissure material rises in the fissure, marks the height to which the 
flood was able to carry its burdens, and in the subsequent ages the meteoric 
waters gaining an access to these chambers, carried with them the lime dissolved 
from the limestones above and re-deposited it in the upper part of the partially 
filled fissure, until later it became solidified and at last received the final sealing 
down of stalagmite, which protected the bones below from further attack. 
Ten fissures are now seen, one only yielding bones. Very interesting it is 
to take out the femur of the Arctic Fox {Cants lagoptis). The nearest country 
to Britain where this animal now lives is Iceland. The remains of the .Spotted 
Hytena have also been taken from the same fissure and also the Alpine snow 
vole, this latter animal helping to prove, as it does, the moderation of the 
so called Glacial Period in the south of Britain.* 
Reverting to the River Shode itself, the guide pointed out that it now rises 
about one and a half miles above Ightham, whereas in earlier times it has in 
succession used two other beds now dry, the steeper one of the two now forming 
a roadway from Boro’ Green to Plaxtol. It was while using this bed that the 
river Shode washed the valuable remains of our Tertiary mammals into the 
fissures. The parly then walked round the original bed of the river, which bed 
was originally a fissure, thus attracting the earliest waters of the stream by 
offering a ready-made bed. We may imagine how swift was that river when 
rushing through a ready-made bed in the hard sandstone. This accounts for 
the steep incline the eleven Selbornians had to climb when mounting the south 
bank of the Shode Valley, a climb of quite 80 feet, the view from this river 
bank being all that could be desired. The party arrived at the Oldbury Rock- 
Shelters. where Mr. Harrison was awaiting their arrival, at about 4.30. These 
dwellings of Palaeolithic man are the best example of their kind to be found 
to-day in the south-east of Pmgland, being natural caves once tenanted by our 
earliest forefathers. These earliest primitive men had to contend with the 
Mammoth, Woolly Rhinoceros, Cave Lion, and many other ferocious mammals. 
The tools of this palxolithic race are found in the vicinity of Oldbur)’ Hill, and 
thus give rise to the name of “ Cmsar’s Camp,” so common a name for such 
places in our country villages. Tea was partaken of at the “ George and 
* See a paper in the Proceedings of the Geologists’ .Association, 1907, by Mr. 
Martin A. C. Hinton, “ Microtus nivalis in Pleistocene times.” 
