NOTES ON THE PROLONGED FROST, 1890-91. 67
In the case of the dead fish, when the thaw set in the surface of the ground
would be the first disturbed and that possibly to such an extent as to bring a layer
of earth over the pond ice, which would eventually sink and entomb the dead
organisms. Similar denudation attending the break up of the frost can now be
observed at the bottoms of fields which have a slight inclination. The result is a
layer of brick-earth deposited, similar to that following a heavy rain, only very
much greater in quantity ; as we have before observed, the work of seasons is here
done in a few weeks.
One other possible case of fossilisation is presented by the dead rooks in the
wood. Suppose, instead of carting away those rooks to manure the field, as was
actually done, they had been allowed to remain. Their desiccated carcases would
have held out but little temptation to the returning rodents and carnivores of the
summer. When the autumn arrived they would have received a covering of
leaves and so easily have passed to the first stage of preservation. The present
speculative position of the conditions under which organisms are entombed is my
apology for venturing upon these suppositions.
The rapid work of the frost in disintegration has been forcibly brought to
notice in the following instance. Some Boulder-clay of a very chalky character
had been thrown out last autumn. Ordinarily the lumps of chalk would have
wasted very slowly under exposure from year to year. Now, the appearance of
the heaps is that of a mass of white slimy clay, the lumps of chalk having quite
disappeared. As bearing upon the work of decalcification the instance is
instructive. That work must now proceed there with greatly accelerated velocity.
Of the effect of the frost in splitting rocks we have also one instance. A pave-
ment in this village (Felstead) is laid with flags of an indurated sandstone. Some
two or three of these flags are broken by the frost, not into laminae, but quite
through the substance splitting the flag. The whole pavement, too, is disturbed.
As to the penetrating character of the frost in different soils accounts vary
greatly. Some pipes were found choked with ice at a distance of more than two
feet under ground. Yet there was no good evidence of the frost having penetrated
the soil to that depth. In compact soil and closely pressed gravel there is good
evidence of a penetration of frost of one foot and some cases are quoted much in
excess.
In passing over some stubble fields a few days after the thaw, I found many
small weeds, notably Cudweed and Pimpernel, looking green and vigorous.
Beneath their roots there was still a frozen pan of ice and this proves that at one
time the plants were completely frozen. It is not easy to see how they emerged
from that state unharmed. Problems affecting the natural transport of plants, not
well understood, might perhaps be helped to a solution by noticing their behaviour
under prolonged frosts.
The varied phenomena attending this great frost serve as an object-lesson to
illustrate the changes brought about by the severity of early post-Glacial times.
Assuming the frosts more severe and prolonged, and the thaws to be of rare occur-
rence, our deaths and migrations of plants and animals would be proportionately
increased, and the erosion accompanying one of those rare thaws would be so
tremendous as to seem perfectly incredible to ordinary readers ; nevertheless traces
of all such changes are legacies remaining with Essex folk to this day.
P.S.—Since writing the above I observe a letter in "Nature," of January 29th,
by Professor T. G. Bonney, referring to the destruction of fish by the frost in
Regent's Park Canal. He also asks whether "such a cause may have acted in
the geological history of the globe." In Nordjenskiold's "Arctic Voyage" there is
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