329 
1878.] Superficial Gravels and Clays. 
are the most characteristic features of the deposit. I had 
the pebbles in some samples of the gravel counted, and 
found that from 80 to go per cent were broken, or more or 
less angular. Thin chips of flint are abundant. Nearly all 
have the edges of the fraCtures a little rounded, as if, after 
they had been broken, they had been shaken together. 
About one-quarter of the rounded pebbles are of quartz. 
There are slight and irregular signs of stratification in the 
lower part of the gravel in some instances ; in others it is 
quite unstratified. Towards the top the stratification is 
more decided, but not continuous. Oblique lamination is 
frequent. It has the appearance of having been suddenly 
accumulated, and at one time. The irregular and fitful 
stratification, the short lenticular patches of sand, the mix- 
ture of sand throughout the gravel, the large stones at the 
base, the great proportion of broken flints with slightly worn 
angles, and the occasional oblique lamination, are all op- 
posed to the theory that the deposit is the result of successive 
layers of materials brought down by a river at different 
times. 
All over the district flint implements of the palaeolithic 
type have been found in the lower gravel. According to the 
unanimous testimony of the workmen they occur nearly 
always amongst the larger pebbles at the base of the deposit, 
and close to the surface of the London Clay. Col. Lane Fox 
has described the position at which were found several flint 
implements at ACton, where the surface of the ground was 
from 75 to 83 feet above the Ordnance datum-line. Most of 
these were obtained from the base of the gravel, and the 
angles were worn and rounded. At one place, flakes were 
found in a thin seam of sand lying below the gravel, and in 
this instance the edges were “ as sharp as when they were 
first flaked off the cores. ”* At Ealing Dean, Col. Lane Fox 
obtained two implements from gravel taken out in the con- 
struction of a sewer which was carried down below the 
general run of the excavations for the foundations of houses. 
According to this excellent authority they occur always at 
the base of the gravel. He says— Here (in the lowest 
stratum of the gravel) the largest flint stones lie, and with 
them the implements, mostly of the dimensions of the larger 
stones, so that it was common lor the more experienced 
workmen to say that they should find no implements till 
they got down into the coarse gravel ; the smaller flakes, 
however, were not so invariably at the bottom.” 
* Quart* Journ. Geo!. Soc., vol. xxviii., p. 457. 
