NOTES ON THE ANCIENT PHYSIOGRAPHY OF SOUTH ESSEX. 199
north-eastward of the Nore Light ; while the ground between the
ancient channels, planed down by the sea like the land north of
Herne Bay and Sheppey, exists as the shoals and sandbanks of
to-day.
Though the chart affords no actual glimpse of the state of things
when the gravels and loams between Southend and Bradwell were
deposited, it evidently adds to the strength of the presumption that
they belong to the valley of the ancient Thames. We may also
infer from inspection of it that since the period at which the Essex
shore-line extended as far eastward as the present coast of the Isle
of Thanet, the Thames, below its junction with the Medway, has
always taken a north-easterly course. And the influence of the
Medway in producing the present aspect of the chart must not
be forgotten. When the ancient Romford stream flowed in the
valley between Warley, Billericay, and Maldon on the one side, and
Laindon, Rayleigh, and Althorne on the other, into the valley of the
Blackwater, and the Thames Valley was where the gravels and loams
between Southend and Bradwell now lie, the Medway, in all prob-
ability, maintained a separate existence for a good many miles out to
what is now sea. Among the channels shown on the chart the most
northerly, which appears between the sands known as Buxey and
Gunfleet, and the Essex shore at and between Clacton-on-Sea and
Walton-on-the-Naze, probably gives us a fair approximation to
the position of the lower Thames Valley when the gravels between
Southend and Bradwell were being deposited higher up. But the
Medway at the same period probably took its course along the
channel, some miles eastward, called the Oaze Deep and the Black
Deep, and joined the Thames some distance to the east of what is
now the port of Harwich. It would seem, therefore, that the marine
denudation, which has given the estuary of the Thames its present
coastline, has reduced the length of the course of the Medway to a
much greater degree than that of the Thames.
The evidence afforded by the chart of the channels of the
estuary coincides with that to be derived from a geological map
showing the shores of both Kent and Essex. From the chart we
gather that at a time geologically recent the land due east of what is
now Essex extended to a more easterly point than the North Fore-
land on the Kentish shore, and has since been planed down with
special rapidity by marine denudation. And a glance at a
geological map shows that here, as elsewhere, the harder rocks