SiGERSON — Fish-remains in Alluvial Clay of River Foyle. 223 
a couple of small ones. Sir George Carew relates that the Lord Presi- 
dent of Munster viewed it in 1600, and Hee found it to be a place of 
exceeding strength, by reason that it was an iland, encompassed with 
a deep lough, the breadth thereof being, in the narrowest place, a o^- 
liver's shot over ; upon one side thereof standeth a very strong castle, 
which at this time was manned with a good garrison, for there was 
within the iland John Fitz-Thomas, with two hundred men at the 
least." This island is now connected to the mainland by a broad tract 
of firm soil and turf-bog. The waters of the lake have fallen, and are 
decreasing ; but Mr. G. Martin informs me that the ex-island is yet 
popularly known as the " Big Island." A great quantity of bones of 
animals has been found in this lake. 
6. Laeigh. — " A. D. 848, Loch Laeigh, in the territory of Umhal 
(Mayo), in Connaught, migrated," say the Pour Masters. IN'ennius adds 
that it ran off into the sea, and that nothing remained of it but its 
place. He sets this down as one of the Wonders of Ireland. 
7. Laeghaire. — This lake is mentioned as existing in 1509, south of 
Strabane, Co. Tyrone ; " the name is obsolete, and the lake has probably 
been drained." — O'D. The Escheatment Maps of 1609 do not show it. 
8. Monann. — It is stated that, a. d. 1522, O'Neill pitched his camp 
at Knockavoe, at Loch Monann, where he was defeated by O'Donnell. 
In the Book of Bally mote, the conflict is called the " Breach of Loch 
Monann." O'Donovan mentions vaguely that this was the name of a 
lake at the foot of Knockavoe. I could find no trace of it, until, by 
the Escheatment Maps, 1609, I discovered that a townland above 
Strabane was then named " Lough monan." The lake was not marked, 
and had then probably vanished. In what manner? It appears to 
have lain at the head of the picturesque little ravine called " Strabane 
Glen," and I believe that this lake also "migrated." Erom the phy- 
sical evidences presented, it seems to have broken bounds (when over- 
flowed by heavy rains), and, ploughing a deep furrow through its old- 
detritic barrier, to have thus formed Strabane Glen," escaping from 
which its waters divided and poured into the Upper Lough Foyle. The 
detritus it bore assisted in the filling up. A sketch of the Glen, from 
the upper end (taken previous to the existence of the present planta- 
tion there), preserved in the Academy, plainly confirms this view. 
It may be added that a vague memory of the outburst might account 
for a traditional prophecy that Strabane was to be drowned by waters 
breaking out of Knockavoe. 
9. Suidhe Odhrain. — It is related by the Four Masters that, in 
1054, this lake "migrated in the end of the night of the festival of 
Michael, and went into the (river) Feabhaill, which was a great wonder 
to all." The name still remains as that of the townland of Syoran, 
parish of Knockbride, Co. Cavan. — O'D. 
The quiet effacement of some of these lakes was due, in part, to the 
destruction of woods, which, as Humboldt remarked, protect the soil 
from the sun, hinder evaporation, condense moisture and exhale it. 
The felling of forests has in several places lessened the rain-ftill, and 
