2 00 PKOCEEDINGS OF THE GEOLOGICAL SOCIETY. 



as well as their zoological differences, are matter for much research. 

 Materials have not long heen obtained whereby we may institute 

 comparisons between the different members even of the British 

 group of Carboniferous rocks, setting aside our intimate connexion 

 on the one hand with the European, and on the other with that of 

 the American continent, especially New Brunswick and Nova Scotia, 

 whose relation to Scotland through the Coal-measures can 

 hardly be doubted. Those beds which overlie the Carboniferous 

 Limestone in the south of Ireland have hardly yet had assigned 

 to them their true place by correlation with those of England; 

 neither has it been satisfactorily settled what is the precise strati- 

 graphical commencement of the Lower Carboniferous series of the 

 North-Devon area, or where the line should be drawn between the 

 Upper Devonian and Lower Carboniferous. Both horizons are 

 fossiliferous, and it is only in the south of Ireland that we have 

 similar conditions, or where a comparison can be instituted be- 

 tween the two. Again, as regards the Coal-measure " shales and 

 flags " immediately overlying the Carboniferous Limestones of the 

 south of Ireland, there can be no doubt that they represent the 

 Millstone Grit of the English Coal-fields. This was the opinion of 

 the late Professor Jukes, who, in the explanatory memoir to sheet 

 No. 137 of the Irish Geological Survey maps, says, " Doubtless the 

 whole of the Coal-measure series of Central Ireland is contempo- 

 raneous with the lower part only of that of Central England, in- 

 cluding the Millstone Grit in that lower part." Prof. Hull also 

 doubts not that through the identification of the Gannister beds in 

 the Leinster Coal-field, which, in the north of England, overlie 

 the Millstone Grit, that contemporaneity, to a large extent, occurs 

 between the English and Irish Carboniferous beds, and this especially 

 on physical grounds. 



Through the close research of the Irish Survey in the Leinster 

 and Munster Coal-fields they are now enabled to trace out and 

 distinguish four divisions : — 1, the Yoredale beds ; 2, the Millstone 

 Grit ; 3, the Gannister beds ; and 4, the Middle Coal-measures as 

 determined in England. Hitherto they have simply been classed 

 under the general term " Coal-measures." 



Professor Hull endeavours to show to what extent the British 

 Carboniferous rocks have their representatives in Ireland ; and he 

 also proposes to establish a "Middle Carboniferous series," which 

 shall include all the strata lying between the Carboniferous Lime- 

 stone and the Middle Coal-measures, including the Yoredale beds, 

 Millstone Grit, and Gannister beds. Mr. Hull is careful to impress 

 upon us the fact that the Yoredale beds of Ireland are more inti- 

 mately associated with the Millstone Grit and Gannister beds than 

 with the Carboniferous Limestone ; hence his reason for proposing 

 the new classification. In England the Yoredale beds are most 

 closely allied to the Carboniferous Limestone, upon which they con- 

 formably rest. 



Mr. Hull minutely describes the main features of the Southern 

 and Northern Irish Coal-districts and their subordinate Coal-fields. 



