4 NOTES ON AN ALLUVIAL DEPOSIT IN THE CANN VALLEY,
worked at least as far up as Chignal Hall, half a mile above the
deposit; and there is a small pit exactly opposite to the deposit,
about fifty yards from the brook.
I have been unable to detect any strata corresponding to those
about to be described on the left or opposite bank of the brook.
The material there seems to be merely gravel, overlaid by a brown
alluvium. It may be observed that the brook here appears to be
eating away its right bank and not its left.
The surface of the "Hop-garden" is composed of a layer of brown
loamy clay, and the upper stratum of the deposit underlies this at a
spot round one side of which the brook flows in a slight curve.
Here it shows as a fine dry and very dark earth, containing remains
of a large number of species of land and fresh-water shells. The
deposit comes to the surface over an area of about one third of an
acre, as shown on the Fig. 1, and I believe it does not extend,
much beyond, although there is an outlying patch at B, which the
rabbits also occupy. I have made several sections at these spots
Fig. 2. Diagrammatic Section. a, Glacial Gravel, partly remanie ; b, Bluish-grey clay ; c, 
d, Black-earth, with shells ; e, Chalky marl; f; Brown loam.
which may be described as follows, and which the accompanying
diagrammatic section (Fig. 2) will serve to illustrate :—
(a) The lowest bed reached consists of many well rolled pebbles, similar to
those now in the brook, mixed with coarse sand. The appearance of this bed is
different from that of the gravel in the pit marked in the plan, being more washed
and less iron-stained, though doubtless the same re-assorted; and many of the
pebbles are encrusted by a calcareous deposit, but not to such an extent as those
now in the brook. Near the surface of the bed I found a tooth, which was
unfortunately lost. I have dug 2 feet into this gravel without finding any change
in its nature : its real thickness is probably much greater than shown. Its surface
is, I think, a little above the present bottom of the brook.
(b) Overlying a is a thick stratum of very fine bluish-grey clay, containing
some very small particles of chalk, especially near its surface. It is homogeneous,