222 
THE GEOLOGIST. 
the valley east of tlie Slievebloom mountains^ also in King's 
County, and in the limestone district of Galway ; indicating a 
north-west and south-east direction, in the line of transport, 
throughout a very large portion of Ireland. This direction, 
however, has not been universal. In the counties of Sligo and 
Mayo there are two ranges, namely, the Ox and the Curlew 
mountains, having nearly parallel directions from north-east to 
south-west. The Curlew consists of reddish-brown sandstone, 
connected with the upper Silurian system ; the Ox mountains, 
situated about twelve miles north of the Curlews, are composed 
of mica slate and granite, whilst both ranges are flanked by 
strata belonging to the carboniferous system. South of the 
Curlews the gravel contains limestone only, and the eskers ex- 
tend in a northern direction up the southern declivities of the 
hills j towards the summit, boulders of yellowish-gray limestone 
are scattered on the surface, while downwards to the limestone 
valley, on the northern side, the surface is thickly covered by 
very large boulders of reddish-brown sandstone, sometimes 
weighing several tons, the largest occurring nearest the ridge; 
towards the base of the Ox mountains these boulders are still 
very numerous, but much diminished in size. Ascending the 
mica-slate ridge of the Ox mountains, small boulders of red 
sandstone still occur, together with small eskers of limestone 
gravel, sometimes remarkable from their forming ridges directly 
across the valleys, as in the valley of Lough Easky. To the 
north and south of this lake the rock is mica slate, but at the 
lake itself there has been an extensive protusion of granite. In 
the line of the road to Easky, two miles south of the lake, the 
valley is crossed at right angles by two eskers, composed of roUed 
fragments of limestone and some clay ; they are thirty feet in 
height, and very steep; their elevation above the plain, from 
which they have apparently been derived, is 250 feet ; numerous 
large boulders of mica slate are strewed over their sm-faces, but 
none are intermixed with the gravel. Approaching Lough 
