LETTERS FROM JOHN BROWN TO S. P. WOODWARD. 137
assistance of Gray's last edition, I have done quite as well as I expected
when I first began these new beds.
You doubtless remember that, when you had the goodness to intro-
duce me to Mr. Forbes, the successor of Mr. Lonsdale, he was so kind as to
offer me a few of the Foraminifera and the sand containing them, the
result of dredging in the Mediteranean [sic.] Probably the multifareous
duties which he is now engaged in may drive his promise into the river of
forgetfulness. I would let it be for the present, but, if he takes too large
a draft of the water of Lethe, perhaps you will be so kind as to speak
a word in season for me at some convenient moment.
Stanway, March 28th, 1843.
I have just found a solitary specimen of the var. of Z. rotundatus which
you showed me at the Geol. Society, and which Mr. Wood has two
of in his Cabinet from the same locality as mine, viz., Copford.6
Stanway, May 8th, 1843.
Many thanks are due to you for the information respecting the dis-
position of the Till and Gravel of Norfolk, contained in your last letter.
It will turn out ultimately that there is no regular sequence of the detrital
beds in the east of England. In my neighbourhood, the Till, in several
sections, covers the red siliceous gravel: in others, the red gravel occurs
over the Till. Your section in the letter shows the Till covering gravel;
while, nearer Norwich, you saw "the Till covering red gravel at Porting."
Since you left me, I have received several offers of exchange of other
fossils for my Copford shells. I have just found a variety, or a distorted
specimen, of Zua lubrica: but I have hunted in vain for another specimen
of ruderata. That variety is indeed scarce. Considering this, how very
singular it was that Mr. Wood should obtain two specimens of that species
with the shells I sent him.
I should esteem it a favour if you would correct the list of the Copford
shells, should it require it, previous to being printed. I forget whether
I had found a specimen of the large Valvata antiqua, figured in Mag Nat.
Hist., p. 547. When you was here, I met with a solitary specimen. It
has lost its animal matter or albumen, and has the same appearance of
age as the rest of the shells of this deposit. Here some species of shells
were in multitudes, while others (such as Valvata, H. ruderata, Bithinia,
and others) are almost excluded; while other species are quite so.
I have collected a good specimen or two of Helix nemoralis, from the
blue lucustrine clay at the Clacton freshwater deposit, since you left
Colchester, and two or three specimens of, I think, Unio pictorum; but
they are much mutilated by the removal, owing to having lost their
animal matter. I think Mr. Wood obtained this shell from Clacton.
In breaking up the bed under the cliff which contains the bones, etc.,
I saw some very large Unios, which I took to be Anodon cygneus, but so
soft that they would not bear touching. The stratum in which I found
the helix is 25 feet below the present surface.
Having occasion to unpack some shells which I gave to our Clergyman,
to be sent to Oxford, from the Copford beds, I met with three specimens
only of Bithinia tentaculata, which I remember very well finding. That is
a scarce species, but still it is found here and ought to be added to the list.
I have no doubt I shall find more in the course of my progress, and I
will reserve a few for you and Mr. S. Wood.
Among the shells for Oxford, I have put a few specimens of the three-
toothed V. pusilla, and have introduced it as a var. of pusilla or a new
species. I do not know the Oxford conchologist, but I shall probably
hear something more about it. Its external form, less number of teeth,
6 This refers to Pyramidula ruderata Studer.