132 THE ESSEX NATURALIST.
this purpose that I sent you 'the only Planorbis that Mr. S. had pronounced
to be new, and that I had found in the Clacton deposit.
The Clacton freshwater formation is highly interesting, regardless
of new species being found therein. I should have thought not so much
of the species that have been termed new had not the authority of Mr.
S.'s name been attached to them. But I would ask, is all doubt removed
respecting them? On the Planorbis in particular, in the first instance
you and Mr. Wood were inclined to think that it was the "mature state
of Planorbis nitidus "Then you thought probably it might be the
young of "Segmentina lineata"; and the specimens in Mr. S.'s possession
you state to be "the young of Zonites, probably Z. cellaria." In case
that any mistake has arisen in this matter—which I begin to think has—
I would advise you to keep the shells till I come to Town, and we will then
compare those which I sent you as P. helicoides with the same specinmse
in Mr. S.'s hands.
You mentioned long ago that I had sent the wrong shells, and if,
when we compare them, there should be a difference, there will be an end
of the matter; but I maintain that the mistake (if any) is not mine. I
sent the only P. of that species from Clacton which I possessed, and,
which I took from the card that Mr. Sowerby had placed them on when he
sent them to me, named as P. helicoides.2
Stanway, Octr. 8th, 1842.
I went to the Copford lucustrine (s. c) deposit this afternoon, to see how
far I was correct when I told you the bed of peaty matter was in some
places two feet below the surface. I saw many of the three-banded helix
(H. hortensis), possessing all their animal matter, and their colours nearly
faded. Thousands of shells in that state I could have obtained from this
thin bed of black peaty matter, two feet below the surface. As I went
on purpose, I measured the small section,4 which probably you will under-
stand by the rough sketch.
Vegetable mould
Yellow loam
black peat
Loam with
chalk boulders
But let it not be thought that there is two feet of loam and mould
over the whole of the space occupied by black peat. The latter crops out
and forms the surface over a considerable portion of the field. I submit
this detail to you to explain away your objection to the recent appearance
of the shells which you saw at my house from this deposit. But the next
time I have the pleasure of your company at Stanway, I will take you
to the place and you will then judge for yourself.
I also beg to inform you that I ordered a barrel of oysters to be sent,
as you directed, and they were sent accordingly on Tuesday last by the
Norwich coach.
2 There has been divergence of opinion respecting the true status of Planorbis helicoides
described by J. D. C. Sowerby in 1840, Mag. Nat. Hist., Ser. 2, vol. iv, pp. 197-201, and it
is clear from these letters that the. best course to adopt, since the type specimen is lost, is to
consign the name to oblivion.
3 On the outer side of this letter there is the drawing of a tomb bearing on its aide the
following inscription:—
"Back to back here we lie
In one grave my wife and I:
When the last trump the air shall fill
If she gets up—I'll lie still."
No information is vouchsafed as to the whereabouts of the tomb.
4 John Brown's sketches and descriptions of local sections have been largely made use of
in the Geol. Sur. Memoir on the "Neighbourhood of Colchester" (sheet 48 S.W.) 1880—En