108
NOTES.
about sixty yards long, the Bagshot sand rose to within two feet of the surface,
while towards the northern end the drift came down deeper and deeper, the gravel
becoming, in its turn, covered by clay containing scarcely any pebbles except at
Rough Sketch of Section Exposed at High Beach.
the bottom, and the Bagshot sand disappearing altogether. The generalised
section here given illustrates the nature of the change. The depth of the excava-
tion was from eight to nine feet.—T. V. Holmes, May, 1887.
Discovery of a Denehole at Frindsbury, near Rochester, Kent.—
Many readers of the Essex Naturalist being interested in deneholes, the
following particulars may be acceptable. At the beginning of March the Rev.
H. Day of Frindsbury kindly informed me of the recent discovery of a denehole
at that place. Various circumstances, however, prevented me from visiting
Frindsbury before April 14th, when Mr. Walter Crouch and I found the pit
covered in and about to be converted into a cesspool. We were, accordingly,
glad to learn that it had been thoroughly inspected, among others, by Mr. F. C. J.
Spurrell, who had taken measurements of it and notes of its peculiarities. It was
discovered during the making of an excavation in the brickyard of Mr. West,
which is situated westward of the road between Frindsbury and Bill Street, and
is only a few yards south of the latter place. We were informed that the section
of the shaft showed more than thirty feet of loamy beds above the chalk, the
thickness of the chalk roof being less than two feet. Mr. Spurrell, in his well-
known paper, states that there are many holes in the chalk hills near Rochester,
but that "they usually enter the chalk immediately, there being no humus what-
ever." This Frindsbury pit thus furnishes a curious exception to the general rule,
being nearly in the centre of a belt of overlying Tertiary ground, which, measured
along the Frindsbury and Bill Street road, is just half a mile in breadth, the chalk
cropping out on both sides of it.—T. V. Holmes, May, 1887.
Deneholes and Cesspools.—The conversion of the newly discovered
Frindsbury denehole into a cesspool reminds me of the fact that in addition to
converted, or perverted, deneholes, the inhabitants of towns and villages situated
on the chalk have been, and in many cases still are, accustomed to drain into cess-
pools excavated in that formation. Indeed, provided that the supply of drinking
water is obtained from some distant and unpolluted source, chalk, from its singular
combination of softness and coherence, is remarkably well adapted to the cesspool
system of drainage. For a long time the liquid refuse percolates through the
sides, so as to obviate any necessity of emptying the cesspool; but gradually, per-
colation almost ceases, in consequence of the deposit of greasy matter. Then,
after being emptied, the sides of the pit are chipped, so as to obtain a fresh chalk
surface, and everything goes on as before. It is obvious that this periodical
enlargement of the pit would often result in the making of an excavation which
might with equal probability be supposed to be either a disused cesspool or a per-
verted denehole. It may be remembered that the deep denehole at Eltham Park,
discovered in 1878, the floor of which was 140 feet beneath the surface, had been
used as a cesspool, in the lime of former owners of the land, for at least a century
—perhaps for two or three, in the opinion of Mr. Flinders Petrie. Yet the only
existing evidence of this former use—apart, of course, from the drain to the shaft
—consisted of a deposit of inodorous mud about six inches thick. The shaft was
capped, when discovered, by a semi-circular brick arch, the crown of which was
only six inches below the surface.—T. V. Holmes, May, 1887.