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nity to that of the freshwater sponge, than is exhibited in the flints 
of the chalk or the cherts of the green sand. 
With respect to the causes of the deposition of the flint, Mr. Bower- 
bank objects to the supposition, that it was influenced by the silice- 
ous spicula of the sponges, because the flint is in no case limited or 
determined by their immediate presence, but is, in all instances, bound- 
ed by the extent of the animal matter of the sponge. He has fre- 
quently observed that the large excurrent canals in the chalk-flint 
spongites are not filled with silex, and that the spicula projecting into 
them have not the slightest incrustation of siliceous matter upon 
their surface ; while on the contrary, wherever a single tube 
or a thin layer of tubes has been projected from the mass into the 
chalk, the silex has been attracted to it. He conceives also, that the 
retention of the spicula and extraneous matters in all parts of the 
flint, may be accounted for, by supposing that the animal matter was 
the attractive agent, acting equally throughout the whole body of 
the sponge. In support of his argument he adduces the siliceous 
shells of Blackdown, and the siliceous corals of the Tisbury oolite 
and the mountain limestone, which contain no spicula, and in which 
it cannot be supposed that previously existing siliceous matter was 
the attractive agent. Lastly, the pyritous fossils of the London, 
Kimmeridge, Oxford and other clays, are also mentioned as exam- 
ples of animal and vegetable substances having exercised an attract- 
ive influence. 
March 25.—Morgan John O’Connell, Esq., M.P; John Samuel 
Enys, Esq., of Enys, in the county of Cornwall; Thomas Joyce, Esq., 
of ‘L'rinity College, Cambridge, and Bath ; John Eddowes Bowman, 
Esq., F.L.S., Hulme, near Manchester; and Viscount Valentia, of 
Arley Hall, Staffordshire, were elected Fellows of this Society. 
A paper was first read “ On the Age of the Limestones of South 
Devon ;” by W. Lonsdale, F.G.S. 
The object of this communication is to show the nature and limits 
of the author's claim to having been the first to infer from zoological 
evidence that the limestones of South Devon would prove to be of the 
age of the old red sandstone; and it was drawn up at the request of 
Mr. Murchison, in consequence of the subsequent adoption and ex- 
tension of the proposed classification by Professor Sedgwick and 
that gentleman; and at the request likewise of Dr. Fitton, in conse- 
quence of the same views having been applied to some of the in- 
fra-carboniferous formations of Belgium and the Boulonnais. The 
paper commences with a summary of the opinions previously enter- 
tained respecting the age of the limestones. ‘The authors quoted are, 
Woodward, 1722; Da Costa, Maton, Playfair, Berger, L. A. Necker, 
De Luc, T. Thomson, Kidd, W. Smith, Brande, W. Phillips, Hennah, 
Greenough, Sedgwick, W. Conybeare, J. J. Conybeare, Buckland, 
Dufrénoy, Elie de Beaumont, De la Beche, Prideaux, Boase, J. 
Phillips, Austen, Murchison, Bakewell and J. de Carle Sowerby. 
By these geologists the limestones are placed in the primary, trans- 
