Whatever may be the ultimate results of the excavations made
at Oroy, Bar-r Hill, Bonnyside, and elsewhere, their importance, so
far, lies in the testimony which they bear to the character of the
compound work known as the Roman Wall—its material, its
formation, and the relation of its parts. No new lapidary
inscription has been unearthed to widen previous knowledge by
direct evidence.1 No additional light has been thrown upon the
events of the Roman occupation. The new facts tending to new
conclusions relate almost wholly to points of structural rather
than historical interest; but, as there is good reason to believe
that they materially modify views hitherto entertained, and as
they suggest, if they do not solve some fresh problems, this
Report is an attempt to place them on record with all care.
Whilst, as reporters, we are mainly concerned to record
observations rather than to discuss theories, it is necessary for
us, at the outset, to notice some aspects of the construction of
earthen walls which have not received full attention from the
scholars whose books on the Roman antiquities of Scotland are
of standard authority.
Under the Roman military system of field entrenchments,
there were two leading methods of erecting a vallum of earth.
One of these was to build it, like a wall, of sods. Hyginus, in
his work on the fortifications of camps, after describing two
kinds of fosses, proceeds to define the various kinds of
1 See, however, Appendix I., for.the altar to Silvanus turned up at Barr Hill
some time after this report was in type.