168 COMPARATIVE ARCHAEOLOGY. 
be seen conspicuously dotting the more fertile straths and 
shorelands of the five northern counties, and the islands of 
Orkney, Shetland, and some of the Hebrides. Outside this 
area only a few sites have hitherto been recognised, viz., two 
in Forfarshire, and one in each of the counties of Perth, 
Stirling, Midlothian, and Berwick. Their structural features 
are so uniformly alike that it has been maintained that they 
were all built at the same time from one plan. The most per- 
fect of these structures now extant is the Broch of Mousa, 
which is thus briefly described in Prehistoric Scotland, p, 390. 
‘“ Tt is built of dry-stone masonry, 50 feet in diameter 
and 45 feet high. At some distance it looks like a truncated 
cone, but closer inspection shows it to be a circular wall, 15 
feet thick, and enclosing an open court, 20 feet in diameter. 
The outside wall-face slants a little inwards from base to top, 
but the inner is nearly perpendicular. An entrance passage, 
5 feet 3 inches high and 2 feet 11 inches wide, with jambs and 
lintels of flagstones, forming a kind of tunnel right through 
the wall, is the only access to the court. Four door-like 
openings may be seen on the wall facing the court near the 
ground level, and about equidistant from each other. Three 
of these openings lead into oval-shaped beehive chambers, 
constructed in the solid wall, and having their major axes in 
the direction of the curve of the wall. The other opens into 
a small recess from which a spiral stair made of undressed flag- 
stones ascends to the top. On mounting the stair for 10 or 11 
feet we find that the surrounding wall, which up to this point 
is solid, with the exception of the beehive chambers already 
referred to, now becomes split into two walls, leaving a 
vacancy, about three feet in breadth, between them. At 
successive intervals upwards this inter-mural space is bridged 
over with flagstones, thus dividing it into a series of galleries 
running round the entire building. The lower galleries are. 
from 5 to 6 feet high, but as we ascend they diminish in 
height. The stair continues its spiral course to the top, in- 
tersecting these galleries, and thus gives access to them all. 
They are lighted from the interior by shallow openings or 
windows, which look into the court. No access to any part 
of this curious structure can be got, except by the passage on 
