328 
Superficial Gravels and Clays. 
Ljuly, 
On the western side of the stream, a deep drain on the 
north side of the railway-embankment gives a continuous 
section down the lower slope of the valley-bank. Fig. 14 
shows the section exposed, at about 20 feet above the Brent 
and about 50 feet above the Ordnance datum-line. Higher up 
the slope, at the large gravel-pit, the upper beds show more 
variety than is usual, the beds a, 3 being composed of a 
succession of clays and pebble-beds. Farther westward the 
Gravel-pit opposite Hanwell Lunatic Asylum. 
a, 1. Sandy clay, with pebbles scattered through it. ci, 2. Pebbly gravel in clay, 
a, 3. An irregular seam of dark loamy clay at base ; then a thick bed of pebble 
gravel in clay matrix ; then dark loamy clay overlaid by pebble gravel, and that 
by sandy clay. c. Yellow sand passing downwards into sandy subangular gravel, 
with large stones at base. 
clay a, 1 thickens, and is extensively worked for brick-making 
at Southall, where the sections correspond exactly with those 
at Ealing. 
The characteristics of the lower gravel are persistent 
throughout the whole district. It consists principally of 
angular and subangular pebbles of flint, with some rounded 
ones from the Eocene beds, and also pebbles and stones, 
generally rounded, of quartz, quartzite, Lydian stone, 
granite, and porphyry. It is extremely sandy, and the sand 
is distributed throughout it, and occurs also in lenticular 
patches. At its base it contains many large pebbles of 
quartzite, some a foot in length, and large unworn or slightly 
worn flints from the chalk. Large Sarsen-stones, 3 to 4 feet 
in diameter, are also found scattered over the district, at the 
base of the gravel. 
The peculiar subangular character of the pebbles forming 
the bulk of the gravel, and the loose yellow sandy matrix, 
