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Address to the Geological Society, delivered on the Evening ofthelSth 

 of February 1831, by the Rev. Professor Sedgwick, M.J. F.R.S. 

 fyc. on retiring from the President's Chair. 



I congratulate you, Gentlemen, on the general Report of the 

 Council laid before the Society this morning. The number of names 

 on our lists has increased by 45 since our last anniversary; and after 

 discharging all the expenses of the past year, besides paying off 835/. 

 of arrears, there remains a balance of more than 450/. to meet the 

 ordinary expenses of the current year. We have now a clear pro- 

 perty amounting in value to 1200/., without including in this estimate 

 our books, cabinets, and collections. Our Library has been enriched 

 with many valuable works, and our Museum with large suites both of 

 English and Foreign specimens. But it is not so much to the in- 

 crease of our various collections as to the great progress made in 

 arranging them, that I rejoice to call your attention. They have 

 received an immense accession of value from the labour bestowed on 

 them by Mr. Lonsdale, whose zeal, self-devotion, and great talents are 

 now well known to you all. I heartily concur in the sentiments recorded 

 by the Committee, and am convinced that no small part of our present 

 prosperity is derived from our official connexion with that gentleman. 



As a duty imposed on me by the office I have had the honour to 

 fill, I now proceed to throw a retrospective glance over the memoirs 

 which have come before us during the past year. To introduce them 

 in chronological order would be attended by no advantage, and would 

 deprive me of the power of showing their relations to each other, 

 and of making such general comments as are compatible with the 

 limits of this address. I shall commence, therefore, with the memoirs 

 relating to the older formations, and pass on to those connected with 

 the great secondary and tertiary groups ; and in this way, without 

 mingling matters of fact and speculation, I hope to lead you to the 

 consideration of one or two great questions which have lately been 

 pressed upon our attention. 



A paper by Mr. Weaver on the physical structure of the South of 

 Ireland demands our first notice. It is accompanied with a geolo- 

 gical map, extending to the limits of a similar map of the East of 

 Ireland, published by him in a former volume of our Transactions; 

 and we have thus obtained from his unassisted labours an accurate 

 geographical distribution of the formations spread over more than 

 half that island. But great as they are, these are not the only 

 obligations we owe to that excellent observer. He has described with 

 the clearest details the various formations of the South of Ireland, 

 commencing with the contorted and highly inclined groups of the 

 older transition rocks, and ending with the unconformable deposits 

 of old red sandstone and carboniferous limestone. 



The order of succession, as far as it goes, is in exact accordance 

 with that of our island, and the beds of transition limestone subor- 

 dinate to the greywacke contain nearly the same series of organic 

 remains as the corresponding beds of Gloucestershire, Cumberland, 

 and South Wales. Amidst the uncertainty of some of our conclu- 



