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. rotund atus 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 Porling.” 
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 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 
bear something more about it. Its external form, less number of teeth, 
6 This refers to Pyramiditla ruderata Studer. 
