10 Proceedings of the Royal Irish Academy. 



Bray Series was remoulded by the Caledonian folding, equally with the 

 stubborn pre-Cambrian floor of Donegal. It is here suggested that the later 

 stages of that folding are responsible for some of the anomalies recognizable 

 in the field. 



Finally, it is obviously tempting to ascribe the overthrusting of the Bray 

 Series on the Leinster chain to an epoch when the chain had already suffered 

 denudation — that is, to the Armorican folding. The relations, however, of 

 the Carboniferous limestone to the Howth block seem to be those of simple 

 overlap, and Greenly," whose work has been so frequently of service in this 

 discussion, remarks that "in the Carboniferous rocks of Anglesey there is a 

 total absence of the isoclinal, shearing, or thrusting structures that recurred 

 so persistently in all the older periods." Isoclinal folding from the south 

 is well known at Loughsliinny and at Clondalkin in the county of Dublin ; 

 and the Armorican overfolding in southern Ireland, accompanied by faulting 

 along the strike, is far more extensive than Jukes represented in his cautious 

 longitudinal sections. But the importation of the Bray Series after it had 

 acquired a cover of Devonian and Carboniferous rocks would, I think, have 

 involved greater disturbance of the Carboniferous strata in the Dublin 

 district than that of which we now have evidence. I should have liked to 

 put forward an Armorican date for the importation, but a late Caledonian 

 date seems to present fewer difficulties. 



31 " Geol. of Anglesey," p. 682 (1919). 



