282 Geological Society. 



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- 

 sions derived from the organic types of deposits remote from each 

 other, we seem in these transition fossils to have a secure starting 

 point ; and whether derived from the flanks of the Austrian Alps, the 

 eastern plains of Gallicia, the central regions of Russia, or the grey- 

 wack6 chains of northern Germany or North America, they have at 

 least a family resemblance not easily mistaken. 



In the limestone of Cork Mr. Weaver observed impressions of the 

 vertebrae of fishes associated with the fossils abounding in the grey- 

 wacke^ slate of the neighbouring country. The fact is in perfect ac- 

 cord with our present knowledge. Impressions of fish have long 

 been known of in some varieties of transition slate ; certain families of 

 Crustacea are eminently characteristic of formations of the same age; 

 remains of fish are commonly found in the mountain limestone of 

 Bristol ; shark's teeth occur in the mountain limestone of Northum- 

 berland ; and I need not perhaps remind you that impressions of fish 

 (sometimes accompanied with Crustacea) are found in incredible abun- 

 dance among the bituminous schists associated with the old red con- 

 glomerates of Caithness. Yet such is the inveteracy of our preju- 

 dices in favour of the hypothesis which admits nothing but what we 

 suppose the simplest forms of animal life into the older strata, that 

 even now we receive the facts opposed to it with doubt and hesitation. 



What above all distinguishes the greywack6 series of the South of 

 Ireland from the corresponding deposits in this country, is the occur- 

 rence of beds of pyritous shale abounding in impressions of Equiseta, 

 Calamites, &c., and containing beds of coal (whence many thou- 

 sand tons are annually extracted) interlaced with, and partaking of, 

 all the flexures of the transition system f. This fact, rendered doubly 



striking 



* [Abstracts of the memoirs reviewed by Professor Sedgwick, in the above 

 Address, will be found in our reports of the Proceedings of the Geological 

 Society, Phil. Mag. and Annals, N.S. vol. vii. viii. and ix. EDIT.] 



f Small quantities of anthracite have been found here and there among 

 the old slate rock* of Cornwall ; and some portions of the oldest division of 



the 



