SiGERSON — Fkh-remaim in Alluvial Clay of River Fotjle. 215 
iiished lake may, for tlie sake of distinction, be called Upper Longli 
Foyle. Taken in connexion with the Lower Lough (to which modern 
map-makers restrict the name of Lough Eoyle), the whole expanse of 
water presented the form of an hour-glass, being narrowed at Derry. 
The Hill of Derry, however, then stood separate from the mainland, 
and formed an island in the middle of the connecting strait. 
It is worth observing that this hour-glass form characterizes several 
Irish lakes, and, with respect to two lakes in the immediate vicinity, 
this Poyle Lough must have resembled Lough Swilly, only that it was 
larger, and Lough Erne, only that it was tidal. 
The question naturally arises — " Was Upper Lough Foyle in ex- 
istence within the time of historical record ?" The answer must be 
in the affirmative, and the fact of its existence in historical times is 
not without importance in the identification of ancient districts, and 
the settlement of localities of historical events. 
Tradition of the former existence of the Lough is embodied in the 
name of " Lough Poyle," which is still popularly given to what map- 
makers call the River Foyle, in its whole extent from Strabane to 
Derry ; for to no other river, however large — not even to the Shannon, 
which is much larger than the Eoyle — is the term Lough" applied. 
The name, therefore, is not intended as loosely descriptive of the pre- 
sent Eiver Poyle, but remains, as a fossil in the language, to show the 
former lacustrine conditions of the Toyle in this place. Dr. O'Donovan, 
who was not aware of this significance of the name, yet records that 
it was the exclusive popular appellation amongst the peasantry, when 
he was engaged in the researches for the Ordnance Survey, nearly 
forty years ago. He also cites authorities to show that it was the 
true ancient name of what is now called River Poyle, and remarks 
that his ignorance of this at first led him into one or two topographi- 
cal errors, as he had naturally imagined that not the ''River," but 
(what we may call) Lower Lough Toyle, was referred to, when the 
name " Lough Poyle" was mentioned. 
Thus, in an unpublished manuscript volume of the Ordnance Sur- 
vey (Co. Donegal, Letters, p. 153), the following passage occurs in one 
of Dr. O'Donovan's letters : — " The farmers of Teboyne never heard 
of a river called the River Foyle. Lough Foyle is the only name of 
the ' watter' up all the way to Lifi'er,^' where the Head of Lough 
Foyle is. Here the Lough (not river) receives two rivers, the Mourne, 
the larger, from Tyrone, and the Pinn, the lesser, from Donegal. 
This (Lifi'ord) is exactly the place where the ancient Irish placed the 
Head of Lough Toyle, and 0' Sullivan, speaking of a battle which took 
place at Lififeria, between O'Donnell and Dockwra's party, says that 
boats (phasellis) sailed up the Lake (Lacus) from Derry to Lifferia. f 
* This is the popular and correct pronunciation of the name (Leithbear), now 
altered to Lifford. 
t In the Annals of the Four Masters, a similar occurrence is chronicled as having 
occurred three and a half centuries before : 
" A.D. 1248, Brian O'Neill, Lord of Tyrone, brought vessels from Lough Foyle 
