SiGERSON — Fish-remains in AUuvial Clay of River Foijle, 221 
suffices to point out the locality, as there was no other to compare 
with it in size. So, after it had become connected with the mainland, 
the appellation of Inch (Inis, the island) was popularly transferred to 
an isle in Lough Swilly, which, though extremely small in relation to 
it, was large when compared with some others. Inch, however, has be- 
come a peninsula in quite recent years. In 1836, the sands between it 
and the mainland had so far accumulated as to permit of a passage 
across, at low water, along the strand road. When a deposit of detritus 
had advanced so far as to make reclamation profitable, human inter- 
ference completed the isthmus. Inch now is no longer an island, 
though still marked as such upon the maps. 
The considerable elevation above water to which sands may attain 
is well shown at the Erne estuarj^ at Ballyshannon, where the sandy 
strand varies from 6 feet at Coolinargit and Ballass to 150 feet near 
Finner East, where it ascends to 192 feet. 
It is not, therefore, strange that the channels described should have 
become choked up, least of all that which united Lough Swilly to Lough 
Foyle. The sand hills are readily accounted for; even the tallest of them, 
Dunberry Hill, is only 79 feet high. The deposit of detritus in the 
channel was supplemented by the growth of bogs above it, and the 
rapidity with which this may proceed maj^ be judged from the state- 
ment by Mr. Grifiiths, in his " Bog Eeports," that he observed one bog- 
grow two inches each year during twenty years. Thus a bog might 
have grown four feet in a quarter of a century, under favourable cir- 
cumstances. 
It is possible that there may have been partial upheaval of the land. 
That this north-western district was subject to disturbance of levels 
within historical times may be inferred from statements in the Annals, 
and from certain physical facts. Thus, I observed deep in a clay pit 
the stump of a tree ; it was impossible to discover with certainty, but 
it seemed probable, that it had been growing in the spot, when, owing 
to a subsidence of the land, the waters rushed over the place, broke it, 
and buried it slowly with silted soil. Now, the Annals, a. m. 3581, do 
countenance such an occurrence, as they chronicle the "eruption" of 
Lough Eoyle in that year. Again, a. m. 375 1, it is related that a Firbolg 
tribe, the Ernai, were defeated on the plain where Lough Erne (which 
takes their name) now is ; after their defeat the lake flowed over them. 
And, Professor W. K. Sullivan communicates the remarkable fact, that 
twenty feet beneath a bog surface, at Pettigo, near this lake, the skull 
of a dolphin has been lately discovered. This indicates that the sea 
once overflowed that locality, through subsidence of the land. That 
there has been upheaval since is proved by the surface of Lough Erne* 
* "I passed over the grand cliffs that overhang the plain of Fweealt ofTooraa. This 
Fweealt is a level district running about five miles along the N. W. banks of the great 
Lough Erne. The name (' Faoi alt') signifies under the height, subrupian. It is 
grand and beautiful, and seems to have been formed when the awful commotion took 
place that formed Lough Erne. It was by a depression of the earth, occasioned by some 
subterranean commotion, similar to the one that in later times destroyed the city of 
Lisbon." — Ordnance MSS., Fermanagh. Letters, p. 41. 
