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326
PROCEEDINGS OF THE GEOLOGICAL SOCIETY.
with unrolled chalk-flints imbedded in a brown and ferruginous clay.
To find similar fossiliferous blocks in situ, I re-examined the district
between this ridge and the Thames, but without success. I found,
however, at another chalk-pit between Lenham Hill and Harriets-
ham Hill, and distant seven-eighths of a mile W.N.W. from the
Lenham pit, some larger sand- and gravel-pipes, in which the more
defined structure led me to conclude that the sand- and iron-stone
of these pipes were not portions of drift, but were part of a de-
posit which once spread in regular beds over these hills, and a por-
tion of which had been let down as it were into these pipes, by the
gradual dissolution of the chalk at these spots, in the way I have
described in a former paper*.
When a subsequent denudation removed the mass of the deposit from
that area, these fragmentary portions of the sands and ironstones
were protected by their position in the chalk, and remain as evidence
of its former wider extension. The Harrietsham pit shows the fol-
lowing interesting section : —
Fig. 3. — Section on the Hill above Harrietsham, Kent,
abode edcba a b a a bed e f e deba
x7* I ■». \ r^v 7
X ' r Km '
Talus.
f, e, Fine light-red and yellow sands, in parts very argillaceous.
d-b, Greenish sand, more or less argillaceous, with a subordinate bed or seam of
ironstone concretions (e). In places c reposes directly on a.
a, Unrolled chalk-flints in brown and black clay. m, Chalk.
I found only a few traces of fossils f in this pit, except some
doubtful vegetable or spongiform casts on the surface of the iron-
stone, of the size of fingers, ramified and entirely covering some
blocks. Flint-pebbles and a few very small quartz-pebbles occur in the
beds b-d, and are often encased in the ironstone, which also some-
times contains unrolled flints, as in bed a. Now, as these pipes are
cylindrical, and as each core of sand is symmetrical, with its several
layers following a like order of succession, and retaining a nearly uni-
form thickness ; and further, as the ironstone-band holds in each pipe
the same relative position, its separate fragments pitching downwards
with the curve assumed by the sand, it is to be inferred that these
are let-down portions of strata, of which the original structure was
horizontal and formed as in fig. 4.

• Quart. Journ. Geol. Soc. vol. xi. p. 64.