GO Professor Buckland's Address. 



portion of his geological map of Ireland. In a paper that accompanied 

 the presentation of this map to us on 22d of May last, he states that he has 

 now coloured, as old red sandstone and carboniferous limestone, exten- 

 sive districts of the counties of Kerry, Cork, and Waterford, previously 

 considered of higher antiquity; imputing his former erroneous opinion 

 to the identity in lithological character of the shales and grits of the old 

 red sandstone and carboniferous systems, with the older rocks in the 

 transition-series. 



Mr Griffiths has also demonstrated by sections the unconformable po- 

 sition of the carboniferous and old red sandstone-formations, which over- 

 lie older and more highly inclined slates in the counties of Kerry, Cork, 

 Waterford, and Wexford. 



Mr Charles William Hamilton has likewise adopted similar changes ; 

 and believes that the slates which occupy a large space between the 

 Mourue Mountains and Dublin are equivalent to those near Cork, which 

 he now transfers to the old red sandstone. 



Mr Greenough, in the new edition of his map of England, represents 

 nearly the same boundaries and order of succession in Devon and Corn- 

 wall as we find in the maps of Mr De la Beche and Messrs Sedgwick and 

 Murchison; but in his memoir connected with the map, adopting the 

 name of Carbonaceous scries for the culmiferous rocks, he substitutes that 

 of Upper killas for the Devonian system of Sedgwick and Murchison (in- 

 cluding under that term the old red sandstone of Herefordshire), and 

 Lower killas for the slates inferior to the Silurian system, which they have 

 termed Cambrian. 



Mr Greenough, in his memoir, also shews by quotations from Dr Mac- 

 Culloch, that the undisputed old red sandstone of the north of Scotland 

 exhibits, at intervals, the same great changes of mineral character that 

 occur in the strata intermediate between the carbonaceous and Silurian 

 systems in the west of England and on the borders of Wales ; and justly 

 infers the inadequacy of any one term to characterize formations which 

 vary so much in lithological composition, that at one place they present 

 the condition of a fine-grained silky slate, at another of sandstone, and 

 at a third that of coarse gravel and conglomerate rock. 



Thus, with respect to the slate-rocks of Devon, Cornwall, and Wales, 

 the difficulties are reduced to those of an unsettled nomenclature ; whilst 

 nearly all parties are in unison as to the fundamental fact of referring the 

 slates of South Devon and Cornwall to the epoch of the old red sand- 

 stone-formation. The term greywacke, however, I rejoice to think, will 

 not be condemned to the extirpation which has been threatened from the 

 nomenclature of geology ; it may still retain its place as a generic appel- 

 lative, comprehending the entire transition-series of the school of Frey- 

 berg, and divisible into three great subordinate formations : — the Devo- 

 nian system of Sedgwick and Murchison being equivalent to the upper 

 grey wacke, the Silurian to the middle greywacke, and the Cambrian sys- 

 tem to the lower. 



