GLASGOW ARCHAEOLOGICAL SOCIETY.
contact with this substance seems to make the black line deeper;
sometimes its shade is a dark blue-black. The lines are protracted
on the south for 6 inches over the kerb, but not on the north.
The fosse (which, as already mentioned, began about 40 yards
west of the last section to take a lower line on the hillside than
the line of the vallum), in approaching this section from the last,
has been, whilst gradually ascending the hill, sinking at the same
time gradually lower in its level as compared with the vallum.
That is to say, its counterscarp top is no longer on relatively an
equality of level with the berm. About 120 yards west of section 9,
the fosse attains the highest point it reaches on Croy, viz., not
far short of 450 feet above sea level. Then it gradually descends.
Under section 10, and for some distance on either side, it has a
precipitous scarp of rough and weathered dolerite standing-
perpendicular or nearly so. Much debris has fallen, and the
shape of the outer mound is not very well defined, but it appears
to be of the type described under sections 7, 8, and 9, its narrow
top making a quick, rounded angle, starting from the edge of the
ditch. Great blocks, 7, 8, and 9 feet long, lie in the ditch,
evidently talus from the face of the cliff above. For a few
yards at one point, the line of the ditch is lost on account of the
quantity of fallen rock, which has fairly covered it up.
At the place where the ditch attains its greatest height above
sea level, the junction of berm and scarp is a couple of feet lower
than the level of the vallum, and the bottom of the scarp is
15 feet lower than the top. Nearer section 10, the present
bottom of the ditch is 20 and 25 feet lower than the scarp
top. The ditch continues to descend steadily between section 10
and the stone dyke near section 11, while the vallum only
descends slightly before beginning to rise again near the stone
dyke. Here the difference in level between the vallum and
the present bottom of the fosse increases rapidly to 20, 30, 40,
and perhaps even as much as 60 feet. The lowest point touched
by the ditch in this part is at the stone dyke referred to, where
the ordinary fiattish berm is lost, as the ground falls away in
an unbroken slant from the vallum to the fosse, and beyond
it for more than 100 feet. After passing the stone dyke, the
ditch takes, for a short distance, a rather higher line, but still