[Nov, U 
S5S Prcceedmgs of Learned Societies, 
strictly Ijelonging to tlie subjacent stra¬ 
tum, but uliich, having lain uppermost 
became involved in tlie first or lowest de¬ 
position of the blue clay. 
Immediately beneath the clay there 
is found a line of about three or four 
inches of the preceding shells imbedded 
in a mass of calcareous matter, the result 
of their disintegratiim. Beneath tins 
are numerous alternating layers of ^hells, 
marl, and pebbles, for about twelve or 
fifteen feet. The shells are those which 
liave been already mentioned 5 but are 
very larely to be met wit!: whole, and 
when entire are so brittle as to be ex- 
tiicated with much difticulty. In sonie 
of these layers scarcely any thing but 
the mere fragments of shells is to be 
found, and in others a calcareous powder 
only is left. 
The pebbles are almost all of a round- 
isli oval form, many of them being 
striped, but differing from those of the 
superior gravel stratum, in being seldom 
broken, in there being few large ramose 
masses, and in their not bearing any 
marks or traces of organization. Many 
of these pebbles are passing into a state 
of decomposition, whence they have in 
some degree the appearance of having 
been subjected to the action of fire: 
small fragments of shells are every where 
dispersed amongst them. 
Beneath the pebbles is a stratum of 
light fawn-coloured sand, of about ten 
feet in depth, and immediately under 
this is the stratum of wliite sand, which 
is about five-and-diirty feet deep, and is' 
here seen resting immediately on the 
chalk. 
At Plumpstead, about a mile distant, 
in a south-eastern direction, there is a 
pit, in which the shells, about two years 
ago, were to be obtained in a much bet¬ 
ter state of preservation than at New 
Charlton ; but this seam of shells, as the 
pit has been dug further in, has by de¬ 
grees become so narrow as to be now 
nearly lost. In this pit, not only the 
shells already mentioned were found, 
but many tolerably perfect specimens of 
trochiformis, Lam. Trochvs 
aperlus, Brander. Arc(D plycerncm^ 
/irc(B Nautic£, and many minute shells 
iii good preservation. All these shells 
appear to liave eiuirtiy lust their animrd 
matter, and, not having become imbued 
with any connecting impregnation, tliey 
are extremely brittle. On t-xaminarion 
with a lens, it also appears that in most 
of the specimens, nothing of their 01 i- 
giiml surface remainSj it having been 
every where indented with impressions 
of the surrounding minute sand, made 
whilst the shells were in a softened state. 
This circumstance is particularly evinced 
in the CpcladeSf in which a particular 
character in the hinge was thus con¬ 
cealer!: in a mass of these shells from 
the Isle of Wight, it appears that the 
lateral teetht are orenulated, somewhat 
similar to those of the JMactra solidoy 
in the gravel stratum; hut in the Cj/- 
clades of Plumstead, this was not dis- 
'coverahle, from th.e injuries which their 
surface had sustained from the sand. 
The fossils of this stratum evidently 
agree witii those found by Lamarck and 
J\I. De France, above the chalk at Grig- 
non, Cuurtagiioi), Nc. and they have 
been just shown, incidentally, to exist in 
the Lie of Wight, In an eastern and 
southern direction from London, this 
stratum, with its fossils, is frequently 
discovered. 
On the heath, near Crayford, about 
four miles eastward of Charlton, long 
vaulted oyster.^’ are found similar to those 
already mentioned. About two miles 
further, in the parish of Slone, is Cockle^ 
shell-hunk, so called, as Mr. Thorpe, th« 
aufhor of Custumale Roffense, says, 
page 254 of that work, “ from the great 
number of small shells there observable.” 
These are the Cyclades already spoken 
of, and w'hich IMr. John Latham, author 
of “ The General Synopsis of Birds,” 
thought bore some resemblance to Tel- 
lina cornea Linn. Histor. Conchy!, of 
Lister, tab. ]59| fig. 14. Mr. Latham 
here also met with a species of Cerithiuvi, 
and another of Turritella. Frag.ments 
of these shells are also frequently turned 
up with the plough in that neighbour¬ 
hood. Thev have likewise been found 
ft/ 
atDartford, at Bexley, and at Bromley, 
to the soiitlnA ard. 
Mr. Thorpe also relates tliat, in the 
parish of Stone, there was a large mass 
of stone, some hundreds weight, full 
of shells, which, was brought from a field, 
and used as a bridge or stepway over a 
drain in the farm-yard. (Custumale 
Rof 'ense, page 255.) 
in several spots in the neighbourhood 
of Bromley, stone is found near the sur¬ 
face, formed of oyster-shells, still ad¬ 
hering to the pebbles to which they were 
attached, and which are similar to those 
wiiich have been just described as oc¬ 
curring at Plumstead and at Charlton; 
the wlmle being formed by a calcareous 
cement into a coarse shelly limestone, 
cuniahiiiig numerous pebbles, The only 
quarry 
