Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/211

 basalt. It is highly desirable that the slopes of these hills should be carefully explored; by examining the channels furrowed in their sides by the wintry torrents, we might hope to ascertain the whole series of rocks here intervening between the primitive formations and chalk.

Murloch bay is bounded on the south by a promontory, which exhibits in the cliffs at its base beds of mica slate dipping towards the north-west under an angle of 45°; but immense slopes of debris (consisting mostly of primitive rocks) interfere to prevent the possibility of determining the structure of the lower regions of the cliff as soon as the bay is entered. Above these slopes red sandstone is seen supporting chalk; the former rock attains the elevation of 560 feet above the beach, the latter extends to the summit of the cliff about one hundred feet higher: between the red sand and the chalk a thin bed of green sand, cementing quartzose pebbles, may be traced. The bed of wacke here occurring in the chalk, has been noticed, page 173, and several whin dykes are observable traversing the red sand. The most remarkable objects on the beach are a large basaltic dyke, which rises in a projecting crag; and still further to the north, near the centre of the bay, the detached conical mount of Drimnakill, which is formed by a vast subsided mass of columnar greenstone, the columns being thrown confusedly together in every possible direction. Near the whin dyke a conglomerate, resembling that of Cushendon, may be seen; so that this rock appears on either side to skirt the primitive formations of Cushleak.

Beyond the mount of Drimnakill, the lower parts of the cliffs are still concealed by slopes of debris, among which subsided masses of columnar greenstone form the prevailing feature; and near this