GLASGOW ARCHAEOLOGICAL SOCIETY.
and there is none. The matter, nevertheless, needs further
One thing is unmistakable. The summit of the vallum had, in
every place where we have examined its course, an easy
superiority in level over the outer mound. In very many,
perhaps in most parts, the stone base of the vallum is higher
than the crown of the outer mound. There can be no question
of the completeness of the " command " possessed by the vallum.
In no part in all its course, so far as can now be judged, could
it have been rivalled, far less dominated, by the outer mound,
although there are many places where the latter would certainly
have afforded shelter to an enemy advancing to attack the
vallum. The outer mound was not a glacis formed on the
modern plan. It raised the level of the ground outside, thus
increasing the relative height of the position which would be
taken by an enemy: and it was not so spread out as to prevent
its being used for hostile purposes.1 As in the corresponding
outer mound of the ditch of the murus in the North English
rampart, so here the "Roman did not construct a glacis—with
slope carefully adjusted so as never to afford cover to an enemy—
on modern military scientific lines.
Of the many problems rising out of the well-marked relation-
ship, on the one hand, between the void of the fosse and the
substance of the outer mound, and the absence, on the other
hand, of any sign of relation between the outer mound and the
vallum, there is one peculiarly interesting. That it is left only
half solved does not lessen its piquancy. Vegetius, it will be
remembered,2 does not associate a fosse of any real size with a
sod vallum. Hadrian, in his address3 to the Commageni, clearly
indicates that a fosse was no necessary complement to a camp
wall either of sod or stone. And Josephus pointedly declares
that, in fortifying their camps, the Romans built the wall first,
1 This and other features of it are touched on later. See p. 148.
2 See p. 30, -supra ; lib. i., cap. 24, only mentions the cavity left by lifting the
sods. This, of course, could in no true sense be a fosse, and accordingly lib. iii.,
cap. 8 (in the fuller account of what is stated in lib. i., cap. 24), says nothing of a
fosse in that connection at all.
3 See p. 32, supra.