2/8 The Irish Naturalist. 



THE RAISED BEACHES OF INISHOWEN. 



BY R. 1,1,0 YD PRAEGER, B.E. 



Two YEARS ago I Spent a short autumn holiday in a solitary 

 ramble round the wild coast-line of Inishowen, the most 

 northerly portion of Donegal and of Ireland, which the con- 

 verging loughs of Foyle and Swilly almost convert into an 

 island, as its name implies. This is a beautiful district, with 

 rugged mountains of ancient schists and quartzites, wild moors, 

 deep bays, and savage sea-cliffs, where the waves of the 

 Atlantic rave and foam. The season was too far advanced 

 for botanizing, and I spent the time in studying the post- 

 glacial geology of the coast, especially with a view of compar- 

 ing the raised beaches of this wild shore with those of the 

 more sheltered shores of the Irish Sea, such as the well-known 

 deposits of Larne and Greenore. 



Culmore was the first point visited. Here, where the 

 River Foyle widens out into the lough of the same name, a 

 low point projects far out into the stream. On the eastern 

 side the sea has eaten into this level tract, and the section above 

 the beach shows lo to 15 feet of horizontally stratified gravels. 

 The material consists almost entirely of rounded flat pebbles 

 of mica schist, with a little quartz and quartzite, in a dark 

 brown sandy matrix, slightly current-bedded near the base, 

 with occasional layers of sharp quartz sand. No shells were 

 found. This deposit covers a considerable area — the whole of 

 Culmore point, and extending one to two miles to the north- 

 ward. It is apparently the creation of the river rather than of 

 the sea, as shown by the brown matrix and the absence of 

 shells. 



Crossing by the ferry to the County I^ondonderry side ol 

 the Foyle, I saw two well-marked sea-terraces rising above 

 the muddy shore near Culmore railway station, to heights of 

 about 10 and 25 feet above high water-mark. These terraces 

 are cut out of a thick and extensive deposit of sands and gravels, 



