NOTES ON ANCIENT DEFENSIVE EARTHWORKS. 149
naturally prefer a site for that massive building as solid and firm
as possible, and would recognise that to place it on a newly-raised
mound of loose material would be the height of folly. But it
does not follow that he would necessarily reject a mound that
had been consolidated by time, and which, indeed, he might not
recognise as being artificial at all. Hence, I think that we are
entitled to assume that wherever we find a Norman Keep on an
artificial mound, as at Norwich and Hedingham, the mound
existed one or more centuries before the Keep.
The question then arises :— In what way, apart from
sections cut across its ramparts and ditches, can we form any
opinion as to the probable date of an ancient defensive earth-
work ? In other words, on what grounds may we conclude,
that it is probably British rather than Saxon, or Saxon rather
than British ?
In many instances the answer must be a very doubtful one,
but as examples I will discuss some of those of the Eastern
Counties.
The position of Norwich, at the head of what was before
the nth century, an estuary, and just above and between the
confluence of the rivers Yare and Wensum, is one that must have
been occupied by some kind of town from the earliest period.
But it is equally obvious that the town must always have needed
earthworks for its protection, as the two streams enclose ground
in which there are no river cliffs, while they would themselves
furnish but a slight defence against a land attack, and form a
highway for an enemy on the water. And I can see no reason
why the partly artificial mound on which the Norman Keep now
stands should not be as ancient as the rest of the defensive
works. For it appears to me that the great development of arti-
ficial mounds for defensive purposes in the Eastern Counties is
simply the result of the extremely flattened contours there, and
has no necessary connection with the habits of any particular
race. Any people, Stone-age or Saxon, whose forts were
palisaded earthworks, would be equally likely to construct huge
mounds. When we call to mind, for instance, that the round
barrows of Salisbury Plain, and the gigantic mound
of Silbury, on Marlborough Downs, were heaped together by
extremely primitive people from the surrounding chalk, there
can be no reason to doubt the capability of such people to form
similar mounds, for defensive purposes, out of the usually softer