1871.] TRETEIYAN 1IXH0D0M0U8 BOKINQS. 231 



towards the vaUeys mentioned by the author. He considered that 

 the valleys had been scooped out by denudation. 



The Pbesident inquired whether the author was provided with 

 any sections showing the thinning-out of the beds. 



Mr. Mitchell, ia 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 ex- 

 isting 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 valley a. He pointed out that the action of 

 water in covering the blocks of Oolite with crystallized carbonate of 

 lime would be protective, and remarked, ia reply to Mr. Etheridge, 

 that the surface of the reefs whilst under water was virtually a sea- 

 bottom on which moUusca lived, so that their occurrence at corre- 

 sponding levels in different hills was not to be wondered at. 



FEBEtTAKY 22, 1871. 



John Thornton Harrison, Esq., C.E., 3 Park Place ViUas, Maida 

 HUl, and 1 Victoria Chambers, Westminster, and M. Hawkins 

 Johnson, Esq., 379 Euston Road, N.W., were elected Fellows of the 

 Society. 



The following communications were read : — 



1. On supposed Borings of Lithodomoits Molltjsca. By Sir W. C. 

 Tkeveltai^, Bart., M.A., F.E.S.E., F.S.A., F.G.S. 



[Abstract.] 



The author referred to Mr. Mackintosh's paper on perforations sup- 

 posed to be made by lithodomous MoUusca* 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 per- 

 forations in situ, he was convinced that they are the work of some 

 of the common terrestrial MoUusca, as maintained by him long ago in 

 Jameson's Edinburgh Journal f. He confirmed Mr. Jeffreys's objec- 

 tion to the assumption that these perforations were made by marine 

 MoUusca, founded on the form of the perforations and their range in 

 height, and remarked that length of time is so essential an ele- 

 ment in their production that their formation is not likely to be 

 observed even ia old quarries. 



The author, in conclusion, referred to some remarks made by 

 Mr. Mackintosh X on the " terminal curvature of slaty laminae " ob- 



* Quart. Journ. Geol. Soc. 1869, vol. xxv. p. 280 ; Greol. Mag. vol. iv. p. 295 ; 

 and ' Scenery of England and Wales,' pp. 288-398. 

 t Vol. xl. p. 396. 

 J Quart. Journ. Geol. Soc. 1867, vol. xxiii. p. 323. 



