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VIL— CORK ROCKS, by G, H. KINAHAN, m.r.i.a., &c. 



[Read, December 20th, 1880.] 



When describing the Cork Rocks in the fourth chapter of the 

 " Geology of Ireland," I pointed out that the Carboniferous rocks 

 north of an irregular line drawn from Kenmare, county Kerry, to 

 Passage West, Cork Harbour, have different relations to the 

 underlying " Glengariif Grits " (Jukes) from those that are lound 

 to exist between the " Carboniferous Slate " and the " Glengariff 

 Grits" (Jukes) south of this line; for while in the latter case 

 there is a continuous sequence between the two, north of the line 

 a similar sequence has nowhere been found. 



On the north side of this line the proximity of the Carboniferous 

 Limestone to the " Glengariff Grits " (Jukes) was pointed out by 

 Griffith, Jukes, and their assistants, while the recent researches of 

 Mr. M'Henry seem to prove that there is an undoubted unconform- 

 ability between the older and newer strata. He has not, however, 

 brought forward any evidence which proves an unconformability 

 between the Carboniferous Slate of S. W. Cork and the " Glengariff 

 Grits " (Jukes). On the contrary, all his work would seem to 

 prove that Griffith and Jukes were right in stating that there 

 was no unconformability or hiatus between these two groups of 

 strata. 



The reason for the unconformability between the Carboniferous 

 rocks north of the previously mentioned line and the " Gleno-ariff 

 Grits" (Jukes) is a subject which as yet has not been properly 

 considered or investigated, at first the problem may appear com- 

 plicated, but if similar phenomena in action at the present day in 

 different places are studied, the difficulty in a great measure 

 disappears. 



In north Europe, Scandinavia divides the Baltic from the seas 

 to the westward. East of Scandinavia the sea bottom for a long 

 period has been continually rising and sinking, while west of 

 Scandinavia the sea bottom has been comparatively stationary. 

 Consequently in the first area the different accumulations ought 



