[ 636 ] 



LVL— GEAVEL TEEEACES; VALLEYS OF THE MOUENE, 

 STEULE, AND FOYLE, COUNTIES TYEONE AND 

 DONEGAL. By G. H. KINAHAN, M.E.I.A. 



[Read, June 1, 1887.] 



[The rivers of Tyrone have a multiplicity of names, as the main rivers and their 

 tributaries, as often as they fork, are each given a new name : thus at Strabane the 

 branches of the Foyle are called the Finn and the Mourne, while the latter, at every 

 divide, has different names : the valley to which we would draw special attention is 

 that now utilized by the railway from Omagh, by Strabane, to Derry, occupied prin- 

 cipally by the Mourne. J 



A traveller along the valley from Omagh to Strabane, and 

 thence along the Foyle to Londonderry, may observe the series of 

 terraces in the margining hill slopes, they disappearing in the 

 vicinity of Derry ; while if he goes north-westward into the valley 

 of the Swilly he will not find any. This remarkable difference in 

 the adjuncts of the Foyle and Swilly valleys has led to research 

 and reflection. 



In connection with Lough Swilly we find it among the loughs 

 mentioned in the Annals as having "broken forth" during his- 

 torical times. As so many loughs, both sea loughs and inland 

 loughs, are mentioned as having " broken forth" at different times, 

 there must be some reason for the records ; the following sugges- 

 tions, therefore, may not be out of place. As pointed out in the 

 previous Paper (ante, p. 632), the climate of Ulster, before the later 

 bogs began to grow, must have been somewhat similar to that of 

 the country adjoining the St. Lawrence 1 at the present time. In 

 this part of Canada there is great heat in summer and great cold 

 in winter, with a small rainfall. Such climatic conditions in 

 Ireland may have caused some of the present sea loughs to have 

 become filled with ice ; while some of the present lake basins (as sug- 

 gested by Mr. Plunkett of Enniskillen, ante, p. 634), may have 

 been hollows occupied by forests. A gradual amelioration of the 

 climate ought, however, to affect the necessary changes ; because 



1 The stone walls of huts similar to those now inhabited by the Lapps and other 

 inhabitants of North Europe, as figured by Du Chaillu and by Nordenskjold, in the 

 voyage of the Vega, are not uncommon in places in the Co. Donegal. 



