Page:Quarterly Journal of the Geological Society of London, vol. 35.djvu/849

ception of the relations of the beds, so far, at least, as the valley of the Kenmare river is concerned.

Fig. 3.—Plan and Section in the Tahilla river near Sneem, showing junction of Carboniferous and Glengariff Beds.

Plan.

Note.—The obliquity is perhaps slightly exaggerated in the plan.

Section.

a. Purple slates, cleavage vertical (Glengariff slates), dip uncertain.

b. Hard grey grits, with bands of slate resting with apparent unconformity on the purple slates.

5. Glengariff Section.—The rugged promontory which separates Kenmare river from Bantry Bay, and which is deeply indented by Glengariff and Adrigole harbours, falls short of the elevation of the Reeks, but is perhaps not less interesting to the physical geologist than the Reeks themselves, owing to the examples it affords of contortions of strata, atmospheric waste, and glacial erosion. The hard and massive beds of grit, often naked or scantily clothed with herbage, are thrown into several grand folds, and often broken off along scarped and serrated ridges, or isolated pyramidal hills, as represented in the following section (fig. 4). Notwithstanding the apparently complex arrangement of the beds, the general structure of the ridge is that of a crenulated arch, in which the lower beds of grit rise to the surface in the centre, and the upper beds of purple slate occupy the sides, dipping beneath the Carboniferous beds which form the shores of the bays and the sides of the valleys which lead down to them.

Excellent sections, showing the junction of the "Glengariff beds" and the Lower Carboniferous or "Coomhola beds," are shown both along the Bantry and Glengariff road and in the banks of the Coomhola river. Both tell the same tale, namely, the junction of the former with the Carboniferous beds, and consequent absence of representatives of the Old Bed Sandstone. On following the section along the Bantry road, we had little difficulty in determining the exact line of division between the two formations, which may be observed near the bend of the road, about 11/2 mile S. of Glengariff Church. Hero the beds of purple slate and hard coarse green grit of the Glengariff series give place to the olive-green slates and