The Earthquake in Relation to Geological Structure. 157
After duly considering the local conditions, it appears
quite unnecessary to us to suppose that this sand was
brought up from any great depth. The farm is situated
close to the junction of the London Clay with a patch of drift
gravel, out of which the sand may have been washed. The
soil is saturated with water just below the surface, and the
ejected water would have to pass through the gravel on its
way upwards and outwards; the finer particles of sand would
thus be washed out of the gravel and carried away in the
streamlet for a greater or less distance, and when deposited
on the surface of the ground, separated from the coarser
constituents, would not be recognized by those unaccustomed
to consider the sorting action of flowing water, and would
thus give rise to the impression that it had been brought up
from some unknown and mysterious depth. In order to throw
further light upon this question Mr. J. C. Shenstone was
good enough to procure specimens of the gravel, which he for-
warded, accompanied by the following remarks :—" We first
dug about two feet deep, exactly at the point where the sand
was washed up; here we came upon a gravelly sand, of
which I send you a sample. We then went to some ground
rather lower and about twenty feet distant from the place
where we first dug; here we came on sand within ten inches
of the surface : of this sand, which was more loamy, I send
also a sample. I may mention that in the second place,
within a few minutes of digging, water began to collect in
the hole, and Mr. Cock, tenant at the farm, tells me that
water lies near the surface in most parts of the Island." The