The elevated Drift deposits near Dublin have been brought under the notice of the Society by other observers. The late Mr. John Kelly has described in our Journal (vol. vi. p. 133) part of the gravels which form the subject of this paper; including the collection at Caldbeck Castle, 1300 feet above the sea. I have already mentioned before the Society (in 1867) the fact of having found marine shells in the Pleistocene gravels near Dublin, at heights of 1000 and 1200 feet above the present sea-level; but I did not wish to offer a paper on the subject until I had collected what might seem sufficient materials for one. These shells are not only in a very fragmentary condition, but also scarce, so that they easily escape notice; and it is necessary to pay several visits, at sufficient intervals, to the few places where the shells are accessible, in order to obtain from thence even a limited collection of detenninable species.

Polyzoary forming a flattened expansion of unknown but apparently considerable size. Branches almost perfectly straight, bifurcating at intervals of from one quarter of an inch to one inch, nearly parallel, united by straight transverse dissepiments, sub-angular or obtusely carinated, and closely striated on the non-cefiuliferous side. About four branches in the space of three lines; measured across the frond. Dissepiments about equalling the branches in diameter, usually placed at intervale of from one line to one-tenth of an inch apart. Fenestrules oblong, rectangular, nearly equal, from one line to one-tenth of an inch in length by two-thirds of a line in width; nine fenestrules in one inch measured vertically, twelve in the same space toeasured diagonally. The fenestrules of contiguous rows nearly, but not quite, at the same level. Celluliferous face unknown.

In the Geological Magazine of last October I have noticed the occurrence of zinc in small quantities in the White Limestone (Chalk) of the Co. Tyrone, and also in the overlying basalt. When that paper was read, exception was taken to the latter part of it, on the ground that-the metal in question had never been known to exist in rocks of igneous origin; but as my analysis seemed perfectly trustworthy, I saw no reason to modify it on the objections then put forward. Since then, whilst making an investigation.– with a different object–on a specimen of basalt from another locality in the neighbourhood of that whence the one originally examined was obtained, I succeeded in again finding zinc in it; and I think it well to mention the fact now, as an addendum to, and as confirming my former statement.

Carboniferous Period.—The Lower Carboniferous rocks, both of the North of England, of Scotland, and of Ireland, afford examples of contemporaneous volcanic action of considerable intensity. The so-called “toad-stones” of Derbyshire, and the great sheets of melaphyre, porphyrite, and ashes of the central valley of Scotland, forming the Kilpatrick, Campsie, and Dairy Hills, appear to have been erupted over the bed of the same sea as that in which were poured out similar materials in County Limerick, forming the well-known Carboniferous volcanic rocks of “the Limerick Basin.” These rocks have been already so fully described by several observers, that I shall confine myself to a very short description, such as is essential to the brief history of volcanic action which I am here endeavouring to draw up.

While spending a few days in the Autumn at Tramore, I chanced to meet with a well-marked example of recent alteration of shore-level; and as on subsequent examination I find it only partially noticed on the Six-inch Map, and not referred to at all on the published One-inch Sheet, or in the Memoir of the Geological Survey of the District, I thought of laying a short note on the subject before this Society.