40 THE IRISH ARAN. 
in thickness, and their longest diameter being 94 feet; and Doo 
Caher. 
Of the last mentioned dun, Doo Caher, or the Black Fort 
(Plate III., fig. 6), I have already made some mention when 
speaking of the first settlement of the Firbolgs at a date which 
tradition places about 3,000 years ago. This structure is 
also placed on the edge of a beetling and lofty cliff, and to all 
appearance is considerably older than the others, the age of which 
cannot, however, be much less than 2,000 years. While the stones 
of Dun Aingus, Dun Oghill, and Dun Onacht retain their colour 
and the sharpness of their edges, those of the Black Fort are much 
blackened, and give the impression of immense antiquity. There 
is a look of mystery about this decaying structure, flanked as it is 
by the remains of an extensive settlement of stone houses, or 
Firbolgic city, which is wanting in the other three duns, which 
almost look as if they had been built within living memory. 
In the middle island there are two duns ; one, Dun Connor, or 
Conchovar (Plate IV., fig. 7), is very large and perfect; of the 
other I know nothing except that I saw it from the sea, as the 
weather never permitted me to land on this island. 
On the southern island may be seen the remains of a dun, in 
the centre of which are the ruins of a medizval fortress called 
Furmina Castle. 
I have several times mentioned the cloghauns, or stone dwell- 
ings, the remains of which are scattered over the island. These 
are low stone structures of two kinds, the earlier ones being little 
more than sleeping places, roofed by a flat stone, in which it is 
impossible to stand upright. Of the second, or beehive-houses, 
there is still one perfect specimen to be seen by clambering over 
a succession of stone walls (Plate IV., fig. 8). This is a circular 
erection, with a roof constructed of circular layers of stone, laid 
with their edges projecting on the inner side, this being repeated 
until the space between them can be closed by a single stone. No. 
doubt the roof was made weather tight by placing sods of earth on 
the stones. The height of this example is sufficient to allow of an 
upright position, but the only means of entrance is by creeping in on 
