the gravel underlying the brick-earth, in the lower of which 
remains of oysters occurred. Even this was not a very 
clear case, but as far as it went it pointed to a slight rise along 
the lower reaches of the Thames, and to a more rapid denu- 
dation of the valley in consequence. 
The investigations of Mr. Spurrell in the Crayford brick- 
pits show that since man lived on the shore of the Thames 
estuary, beds of sand and gravel, containing remains of the 
mammoth and tichorhine rhinoceros, of the Corbicula fluminalis 
and Unio littoralis, have accumulated to a depth of at least 
37 feet over the remains of man. If we may assume that 
these were estuarine deposits, they must have been upheaved 
some of them more than 50 feet above the level of the river. 
Having recently examined the ground carefully with Mr. 
Spurred, and dug out numbers of the worked flints with my own 
hands, I am convinced that the evidence is quite satisfactory. 
In the Somme valley, the other valley of greatest import- 
ance in our inquiry, there is a shell-bearing bed at Menche- 
court,* but this is also at quite a low level, and merely points 
to estuarine conditions running further up the valley, but to no 
extensive elevations in palaeolithic times ; and along the 
valley there appears to be no trace of any higher beds, with 
marine or estuarine remains, as yet discovered, although the 
flanks of the valleys have been so extensively cut into for 
brick -earth and gravel. 
We will now see what we can obtain from an examination 
of the coast lines of the Channel. 
Here, of course, we have to deal with raised beaches and 
submerged forests, and, to begin, I will offer a few words of 
caution, as it is not every deposit containing sheds lying 
above the highest tide that can fairly be considered a raised 
beach ; nor is it every old forest over which the sea flows at 
every tide that can be truly called a submerged forest. 
It is wed known that, in a bay, especially where the sea 
rods in over a long-shelving shore, the waves run up far on 
to the beach, carrying sheds and stones above the line to 
which the water could raise them against a wad or cliff. So 
when, from the destruction of a headland, or other local 
change, the sea cuts down such a shelving shore, and leaves 
a cliff, the base of which it scours, it would appear, at first 
glance, that we had there, in the highest portion of the old 
sand margin, a raised beach, and it would be received as 
evidence of an elevation of the coast. 
* Prestwich, Trans. Soc. Ant Lond. 
