GEOLOGICAL NOTES IN THE NEIGHBOURHOOD OF ONGAR. 89
Gravel Pit by the high road, nearly three furlongs south of
"Bryces." 333 feet O.D. Gravel (not mapped).
The section is five feet deep and shows beds of sand
with scattered pebbles—masses of pebbles, many on
end. Masses of mottled reddish sand and clayey
sand. The whole without a sign of stratification.
The stones are mainly flint pebbles, but there are a
good many subangular flints and few small quartz
pebbles and some flints very little water-worn.
The pebbles in these gravel patches are most probably derived
from pebble beds of Bagshot age. The subangular flints probably came
from the south, brought by streams or rivers, or they may be relics of
a very old submergence. Even if we do not believe in a submerg-
ence at the time of the deposition of the Boulder-Clay, there is every
probability that the sea covered the south of England during some
part of the long time which elapsed between the Bagshot Period and
the Glacial Period, and during that submergence many a foreign
rock or pebble may have been scattered over the sea bottom. In
this way I account for the presence of the quartz boulders which I
found in the Berkshire plateau gravels and for the foreign rocks
described from the same gravels by Mr. Shrubsole.6
The presence of unworn flints and the absence of stratification
lead me to believe that the gravels at Dudbrook and Bryces were
much disturbed and the materials rearranged in Glacial times. Per-
haps it is most correct to call them rearranged pre-glacial gravels.
There is, I believe, a patch of this rearranged pre-glacial gravel
on Norton Heath.7 I did not see a very good section, but there
seemed to be a good deal of quartz and many unrolled flints in the
gravel. Level about 320 feet O.D.
Near Chiver's Paun Manor House, on the south of Norton
Heath, there is a large gravel pit. The gravel is over 6 feet thick and
glacial erratics are very abundant.8 The place is mapped "Hill
gravel of doubtful age," but I fail to see why it should not be called
Glacial gravel, for I have no doubt it is of Glacial origin.
At Nine Ashes I saw a small pit in gravel of flint pebbles,
subangular flints, and quartz ; there was, however, no good section.
(Mapped loam.8)
6 Quart. Journ. Geol. Soc. (1892), vol. xlviii., p. 34, and (1893). vol. xlix., August number.
7 Whitaker, op. cit., p. 276.—Mr. Penning's notes.
8 Monckton and Herries, Proc. Geol. Assoc. (1891), vol. xii., p. 110.
9 Whitaker, op. cit., p. 297.—Mr. Bennett's notes.