482 Proceedings of the Royal Irish Academy. 
superincumbent structure: thus the nineteenth century native of 
Coolnahinch is now profiting by the labours of countlessly removed 
past generations, and is quite unconsciously using fuel that may be 
considered in part artificial. 
It may be here noted that the foundations of the submarine 
crannog at Ardmore, discovered by R. J. Ussher (see Lake Dwellings 
of Lreland, p. 216), rested on a growth of peat over a marly sub- 
stratum. One of its mortised beams here delineated (fig. 2) is almost 
a facsimile of those shown at p. 247 of Lake Dwellings of Ireland ; 
at p. 74 of Ancient Scottish Lake Dwellings; at pp. 6 and 437 of Lake 
Dwellings of Switzerland. 
The remaining surface of the crannog of Coolnahinch—strewn 
with detached heaps of stones, all bearing marks of fire—is very 
uneven ; but as it is higher than the level of the surrounding tract, 
it is much used by the peasantry as a drying-ground for their turf; 
and to serve as protection from damage by cattle a fence (EE) has 
been formed along the eastern side. The stones on the surface of the 
crannog are a kind of sand, or rather pudding-stone, that is not 
Fig. 2. 
Beam from Ardmore Submarine Crannog, 1 foot 43 inches in length, in the possession“of 
R. J. Ussher. 
common in the locality, the prevailing rock being grey slate. On 
the western side of the island these heaps are largest ; on the eastern 
or fence side (EE) the surface dips considerably. Over this part of 
the crannog there has grown (of course since it was deserted) a layer 
of brown fibrous peat, known in the locality as ‘‘slane turf.’? This 
‘“‘slane”’ is about two feet thick along the fence; but it fines off 
towards the centre, where it disappears. 
Carbonized vegetable remains, with masses of charcoal, were 
found with the calcined stones all over the surface of the crannog, 
wherever the green sod covering the site was turned up; but the 
crannog is being rapidly turned over in the process of turf-cutting. 
Two years ago Mr. Smith found no difficuty in procuring quantities 
of this calcined vegetable matter, tolerably free from foreign mixture ; 
for wherever the earth was exposed for any time to the weather, the 
rain washed the earthy matter away, leaving the grain quite clean, 
except for a few pebbles and bits of charcoal. On repeating his visit 
lately, Mr. Smith was not so successful: the grain on the crannog 
