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Published online by Cambridge University Press: 01 May 2009
In a paper entitled “On Traces Of Glacial Action near Llandudno,” printed in the Geological Magazine, Vol. IV. p. 289, I described certain indications of glacial action (as they appeared to me) upon the two masses of Carboniferous Limestone, well known to visitors at Llandudno under the name of the Great and Little Ormesheads. The principal conclusion at which I arrived was that, “after the limestone hills of the district had acquired their leading forms by upheaval and marine denudation, the whole district was depressed. The summits of the low rocky islets thus formed became capped with ice-fields, which in places descended in glaciers into the sea. At times, very probably, they were united to the mainland by pack or coast ice.” I then supposed that, after some minor changes, “the whole was gradually upheaved above the sea, probably—at any rate, in the case of the Great Ormeshead—not quite uniformly.”
page 484 note 1 During my examination of the large boulder mentioned above, I was led, in a search for ‘Pholas’ burrows, to look narrowly into a crack about an inch and a quarter wide, indicated in the middle of the side towards the spectator, in the plate. At a depth of about three inches it appeared to be choked with angular fragments of limestone, among which could be seen a shell, which, when uncovered a little, proved to be Buccinum undatum, wedged in with its spire downwards. As it had a very ancient appearance, I supposed that this would make for the marine theory; but a little poking at it with a chisel showed that the fragment in contact with it above was bone, probably of a sheep. Beneath the Buccinum, was a shell of Helix aspersa. Further examination of the crack showed that it extended to the upper part of the stone, and widened in that direction, so as to be at last three or four inches across. It was filled with limestone fragments to within a foot or so of the top; on removing the topmost of these, I found a fresh bone (part of the clavicle (?) of a lamb). I suspect, therefore, that the Buccinum, with the bones, were dropped down the crack by a raven or a gull. I was confirmed in this view by finding that I could not succeed in extracting them from the crack by the lateral aperture.
page 486 note 1 See note and references at the end of Mr. Darbishire's paper.