THE RIVER-WALLS OF ESSEX. 281
THE RIVER-WALLS OF ESSEX.
BY PERCY THOMPSON, F.LS.
(Read 24th February, 1945)
THE river-walls which extend from London to the sea coast
and which prevent the Thames from flooding our low-
lying Essex marshlands consist of banks of earth thrown up to
a high angle and often faced on their river-ward aspect with rag-
stone obtained from the Upper Greensand beds of Kent.
Although so familiar to all who use the river, the origin of
these so-called "walls" is obscure. In popular opinion they
were built by the Romans, but no proof is forthcoming to
substantiate this view ; which is at least doubtful, since we
know from recent research1 that a subsidence of some 12 to 15
feet has occurred in the lower Thames valley since Roman
times : so that land now liable to flooding, but for the protection
given by the walls, might then have been well above the level
of highwater and protecting walls unnecessary, especially
towards the east.
Some of the river-walls may have been in existence at the
time of the Saxon Heptarchy (i.e., about the end of the sixth
century a.d.) in view of the fact that King Offa endowed the
monastery of St. Peter, Westminster, with two hides of land
in "Hamme" [identified with North Woolwich, on the Essex
shore of the Thames], and this land is referred to in Domesday
as being arable and woodland, so that either it must have been
protected from the river at high spring tides to enable it to be
cultivated or subsidence had as yet not made it liable to flooding.
Not, however, until the 12th century do we meet with any
documentary mention of the walls, and although negative evidence
is always unreliable it seems probable that only in later Saxon
times did it become necessary to construct them.
In Magna Carta (a.d. 1215) the liability for owners to
maintain the banks was limited to those banks which "were
in defence" in the time of Henry II (i.e., 1154—1189)2.
The earliest documentary evidence known to me is contained
in a Fine of a.d. 1198-99, which mentions half an acre of land
at Tilbury as lying towards the south, next the Wall (Wallam) ;
another Fine, of date a.d. 1201-02, refers to 10 acres of land
in the fresh Marsh called "the Falge" next the Wall (Wallam)
towards the north, in East Tilbury.
1 A. G. Francis. "On Subsidence of the Thames Estuary since the Roman Period."
Essex Naturalist, xxiii, pp. 151-170.
2 Sir H. L. Smith, History of East London, 1939.