278 



The Irish Naturalist. 



November, 



shore. A second ridgy hill (Knocknaveen), attaining 729 feet, 

 forms a prominent feature in the centre of the island, while a 

 third parallel one. much lower but still conspicuous, extends 

 along the south-eastern edge. All these ridges, as well as the 

 high cliffs which form the extreme north, and on which the 

 lighthouse stands, show clearly in the subjoined sketch made 

 from the train near Mallaranny, ten miles to the north-east. 



The Knock- Croggan 

 Quay, naveen. Lough. 



Croagh- 

 more. 



Light- 

 house. 



•WP 



Fig. I. — Outline of Clare Island, from the north-east. 



The ground falls in all parts from the north and west towards 

 the south and east, thus protecting the surface to a limited 

 extent from the fury of Atlantic gales. The cultivated and 

 inhabited portion of the island — it harbours some seventy 

 families — lies along the eastern and southern margins. The 

 following sketch-map shows roughly the reclaimed area, which 

 seldom extends above 200 feet elevation, and the 500 and 1,000 

 foot contours. Much of the land formerly cropped has been 

 allowed to relapse into poor pasture. Every part not under 

 cultivation, including the hill-tops and sea-cliffs, is closely 

 grazed by sheep, cattle, horses, and donkeys. The live-stock, 

 which is the pride of the islanders, is certainly pretty severe 

 upon the vegetation. 



Clare Island is formed of Ordovician and Silurian slates, 

 grits and conglomerates, dipping south at high angles, with 

 some mica schist, and a little serpentine ; a few dykes of 

 dolerite and felstone occur. At the eastern end, Lower 

 Carboniferous sandstone occupies a small area, resting in 

 almost horizontal beds on the older series. The main ridges 

 of the island follow the strike of the slates ; in the south-west 

 the almost vertical bedding produces some remarkable cliff 

 scenery. The lower parts of the island — i.e. the east and 

 south — are covered with drift. In the north-east the drift is 

 thick, and forms steep sea-slopes over a hundred feet in height. 



