.A., F.L.S.

[Read June 3rd, 1858.]

The London clay is very tenacious, and near the surface is generally of
a brown colour, probably owing to the decomposition of the iron pyrites
which it contains. It abounds in selenite or sulphate of lime, and in
nodules which often contain organic remains. Fossil wood with _Teredo
antenautae_ is also met with, and pyritous casts of univalve and bivalve
shells. Lower down the stratum becomes more compact and is of a bluish
or blackish colour, and its fossil contents are in a fine state of
preservation. During the last summer, while examining the London Clay in
the vicinity of Highgate in search of fossils, my attention was directed
to certain appearances in it which I could not account for. This led to
a further examination, when I found they were produced by the borings of
_Lumbrici_ or earth-worms. These appearances consisted of long tubes
passing nearly perpendicularly through the clay and terminating in
receptacles or _nidi_, each tube leading to a separate receptacle. As
these receptacles occurred in large numbers, I had an opportunity of
examining a great many of them with various results. In one instance, I
found a dead worm coiled up; in another, a portion of a worm protruding
into the lower part of the tube. Again, _nidi_ were found partially
filled with only the casts of worms, whilst others contained more or
less of a species of Conferva; and, lastly, I obtained some with the
cavities partially or wholly filled up. The receptacles varied in shape,
from a sphere to an oval, and were extremely thin and fragile. They also
varied in size from a pea to a nut. Externally they presented an
appearance so singularly contorted, that I could not help considering
they were moulded from the casts of worms. They did not appear to have
any attachment to the surrounding clay, except at the point of junction
with the tube; and the clay beneath them presented no unusual
appearance.

Internally they generally exhibited impressions of the worm; but
occasionally I detected some of the round and contorted appearances
which I have mentioned as being so conspicuous on the outside. I cannot
speak with precision as to the length of the tubes, as the clay when
examined had been broken up into large rough masses in digging for the
foundations of houses. The largest noticed was about three inches long,
and the general width one-eighth of an inch. They often run parallel to
each other, but at une