towards the valleys mentioned by the author. He considered that the valleys had been scooped out by denudation.
The President inquired whether the author was provided with any sections showing the thinning-out of the beds.
Mr. Mitchell, in reply, stated that he had seen both sides of what he regarded as coral reefs. He remarked that his hypothesis had been arrived at by induction, but that the question might be put strongly in a deductive form, by inferring from observations on existing coral reefs that those of the Oolites must have been covered up as islands. He remarked that if the oolitic beds had slipped, as described, upon the underlying clays, they could hardly range on opposite sides of the valleys. He pointed out that the action of water in covering the blocks of Oolite with crystallized carbonate of lime would be protective, and remarked, in reply to Mr. Etheridge, that the surface of the reefs whilst under water was virtually a sea- bottom on which mollusca lived, so that their occurrence at corresponding levels in different hills was not to be wondered at.
February 22, 1871.
John Thornton Harrison, Esq., C.E., 3 Park Place Villas, Maida Hill, and 1 Victoria Chambers, Westminster, and M. Hawkins Johnson, Esq., 379 Euston Road, were elected Fellows of the Society.
The following communications were read : —
1. On supposed Borings of Lithodomous Mollusca. By Sir W. C. Trevelyan, Bart., M.A., F.R.S.E., F.S.A., F.G.S.
[Abstract.]
The author referred to Mr. Mackintosh's paper on perforations supposed to be made by lithodomous Mollusca* in the limestone of Lancashire and elsewhere, and stated that from his examination of specimens in the Society's museum, and of examples of these perforations in situ, he was convinced that they are the work of some of the common terrestrial Mollusca, as maintained by him long ago in Jameson's Edinburgh Journal†. He confirmed Mr. Jeffreys's objection to the assumption that these perforations were made by marine Mollusca, founded on the form of the perforations and their range in height, and remarked that length of time is so essential an element in their production that their formation is not likely to be observed even in old quarries.
The author, in conclusion, referred to some remarks made by Mr. Mackintosh‡ on the " terminal curvature of slaty laminae " ob-
- Quart. Journ. Geol. Soc. 1869, vol. xxv. p. 280 ; Geol. Mag. vol. iv. p. 295 ;
and ' Scenery of England and Wales,' pp. 288-398.
† Vol. xl. p. 396.
‡ Quart. Journ. Geol. Soc. 1867, vol. xxiii. p. 323.
