the wall of the dyke has undergone a great degree of induration, its cement assuming the appearance of a compact hornstone; thus it has been enabled to oppose to the sea a resistance almost equal to that of the basalt itself, and is still seen adhering on the sides of the advanced crags above mentioned.
From the most northerly of the two cliffs a ridge extends towards the ascent of Lurgethan on the south-west, running through the townland of Killnadore; in several points along this ridge, and particularly at Nockans and Tully, a very remarkable formation of porphyry may be traced. Dr. Berger[1] considers it as clinkstone porphyry and describes two varieties here noticed by him; one of them distinguished by a reddish brown and the other by a bluish grey colour, both containing concretions of glassy quartz and of calcareous spar, the latter of which in the first variety occurs in the form of detached crystals, but forms veins in the second. He adds that it crops out in independent masses. He mentions also Court Martin, an old entrenchment near Cushendahl, on the road to Cushendon, as another locality of the porphyry.
From the observations made by Mr. Buckland and myself on these rocks we were induced to believe that they were associated with and subordinate to the old red sandstone. The position of the ridge of Killnadore is distinctly indicated in the section.
On the north of this ridge is the mouth of the river Balyeemin on which the little village known by the double name of Newton
- ↑ In an earlier part of the paper it was erroneously stated that this porphyry had escaped Dr. Berger's notice, and the editor did not discover his mistake till the state of the press tendered it necessary to substitute acknowledgment for correction. His oversight arose from the circumstance of its being described among the floetz trap series, though its connection with the old red sandstone and its position near the foot of Lurgethan, while the floetz trap is confined to the summit of that mountain, certainly renders its introduction in rush a place ah act of very questionable propriety.
