162 Mr. Griffith, on the Order of Succession of the Older 



which I think it incumbent on me shortly to reply to ; and I 

 hope to be able to show that my map is correct, and that 

 Mr. Hamilton is incorrect in every case in which he has 

 thrown a doubt on its accuracy. 



The main points of difference between Mr. Hamilton and 

 myself are; 1st, he is opinion, that in the county of Kerry, 

 south of Castlemaine Bay and the lower Lake of Killarney, 

 the old red sandstone overlies unconformahly those schistose 

 rocks which in my map are comprehended under the general 

 name of transition, and which include the Silurian system 

 and the older or Cambrian slate=*. 



2nd, That the old red sandstone strata of the Gap of 

 Dunloe extend uninterruptedly in a southern direction from 

 the gap to the summit of MacGillacuddy's Reeks, from which 

 point they dip to the south, and are succeeded conformably 

 by a new series of rocks which Mr. Hamilton considers to 

 belong to the Devonian system. 



Srd, That the band of yellow sandstone shown on the 

 geological map as underlying the carboniferous limestone in 

 the valley of the River Roughty at Kenmare, does not exist 

 there. 



In illustration of these views Mr. Flamilton has given two 

 sections, the first of which extends from the gap of Dunloe 

 in a south-eastern direction across Toomies and Glena 

 Mountain to the middle or Turk Lake of Killarney, and thence 

 over Turk and Mangerton Mountains to the valley of Ken- 

 mare ; the second is a representation of Mr. Hamilton's view 

 of the strata as they appear on the west side of the gap of 

 Dunloe. 



In both of these sections Mr. Hamilton has represented 

 the old red sandstone as resting unconformahly on the older 

 schistose rocks, which he calls " Cambrian ;" but I state with- 

 out fear of contradiction that his section and statements are 

 incorrect in this respect, and that in the locality in ques- 

 tion the old red sandstone has been deposited conformably 

 on the older slate, and in a descending order graduates im- 

 perceptibly into that rock. This is also the opinion of Mr. 

 Weaver, who considers the whole to belong to the transition 

 series; and Capt. Portlock, in his presidential address to the 

 Geological Society of Dublin, appears to entertain the same 

 opinion. 



In the first volume of the Journal of the Geological Society 

 of Dublin, page 285, Mr. Hamilton describes the old red 

 sandstone as forming " an anticlinal axis on the summit of 



* See note appended to the large Geological Map of Ireland. 



