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'262 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. .Jan. 23,
hilly district, stretching from Croydon to beyond Gravesend, occu-
pied solely by this sandy and pebbly series reposing on a base of
chalk, and only in a very few cases showing a capping of the London
clay. The difficulty is, whether we are to consider any of the pecu-
liar fossiliferous, sandy or conglomerate beds of Woolwich, Bromley,
and adjacent districts as a fuller development of the basement stratum
of the London clay, or whether they all belong to a distinct and
underlying series. I am rather inclined, on structural evidence, to
the latter opinion ; nevertheless, on palseontological grounds it might
be presumed that a passage here exists between the two series. We
however yet feel the want of a few good sections to settle clearly this
point, to which I shall have occasion to revert more fully in another
part of this paper.
At various points beneath the outlier of London clay at Shooter's
Hill are indications of the basement pebbly bed of the London clay ;
and some years since there seems to have been at Plumstead a deeper
and better section than any now existing ; for in some of the early
numbers of the ' Mineral Conchology,' Mr. Sowerby described a group
of shells from this locahty which bore a strong general resemblance
to those of the bed we are describing. The following is a hst of the
shells he enumerates : —
Cardium Plumsteadiense, Sow. Fusns labiatus, Sow. sp.
Calyptraea trochiformis, Lamk. Melania inquinata, Defr.
Cerithium variabile, Desk. Neritina uuiplicata, Sow.
Fusus latus, Sow. sp. Panopaea intermedia, Sow.
costatus, Sow. Pectunculus Plumsteadiensis, Sow.
■ gradatus, Soiv. sp. Planorbis (?) hemistoma, Sow.
Mr. Morris informs me that he has here found casts apparently of
the Cyprina Moi'risii.
From Mr. Sowerby' s description, I cannot learn whether the fos-
sils were all found in the same bed ; I should be uiclined to beheve
that they were not. The Flanorhis hemistoma, Neritina uniplicata,
and some species of Fusus, I have never found associated with the
PanopcBa intermedia and Cardium Plumsteadiense, so characteristic
of the basement bed of the London clay. Still, if this bed was here
accumulated under more flmdatile conditions, there would be no valid
objection to such an association of organic remains in this part of the
series.
About six miles to the north-west of this spot, a cutting on the
Eastern Counties Railway, at Maryland Point, near Stratford-le-Bow,
exposed a very illustrative section. (See fig. 9.)
Fig. 9. — Section near Stratford.
w. E.
'.',■'■.■:'. i','.'.'..'/^--,":'-\'^i' Ochreous flint gravel.
b. Brown clay (lower part of London clay?).
Clayey green sand. 2. Yellow and ochreous sand. 3. Yel-
low and ochreous sand, with round flint pebbles and nu-
merous fossils. It occasionally forms calcareous concreted
1 I L masses.
3 rf, 1 to 3. Brown, dark grey and yellow clays. 4. Yellow sand
^ I (5 feet), reposing upon a considerable thickness of mottled
J clays not exposed.