Ejnahan and Baily — Report on EocJcs, 8fc. 



477 



The reasons for and against the unconformability bet\veen the rocks 

 of the Pomeroy series and those of ''Lower Old Eed Sandstone" type 

 may be tabulated as follows : — 



Foe. 



The Aghafad conglomerate blocks 

 seem to be the untransported debris of 

 tbe basal bed of the " Lower Old Eed 

 Sandstone" ; and if this dips at a simi- 

 lar angle to tbe rocks a little vraj off 

 towards tbe soutb, all ougbt to lie un- 

 conformably on the fossiliferous rocks 

 to the north. 



As the rocks at present appear, in the 

 north-east comer of Comamaddy, there 

 seems to be an unconformability between 

 the two series. 



The general strike of the rocks of the 

 Pomeroy series would suggest that they 

 extended unconf onnably under the later 

 rocks to the west. Moreover, to the 

 westward, about two miles X.E. of Sis- 

 mile-Cross, adjoining the Camowen ri- 

 ver, there is a small exposiire of rocks, 

 very Kke those of the Pomeroy series, 

 standing at a high angle and striking at 

 the later rocks. Unfortunately this ex- 

 posure is so small, that it is impossible 

 to say for certain the true age of these 

 rocks. 



The rocks of the Pomeroy series ap- 

 pear to be much more broken up and 

 displaced by faidts than the overlying 

 rocks. 



The fossHs of the Pomeroy series are 

 almost entirely of English Caradoc-Bala 

 types (Cambro-Siliirian). 



To the S. "W. of the area of the rocks 

 of the "Lower Old Red Sandstone" 

 type, at Lisbellaw, in the county of Fer- 

 managh, there are rocks very similar to 

 those of Pomeroy, and containing some 

 fossils identical in species. On these 

 Lisbellaw rocks the rocks of the ' ' Lower 

 Old Eed Sandstone" type Lie unconfor- 

 mably. 



Agaes'st. 



All the rocks in the Aghafad section 

 have a similai- strike, and dip in one 

 dii'ection. The rocks in Lm-ganeden, 

 a little south of the Aghafad conglome- 

 rate, are very similar, if not lithologi- 

 caUy identical, with some of the rocks 

 of the Pomeroy series. 



In the valley at the N. E. of Coma- 

 maddy there are evidently various con- 

 current faults ; therefore the rocks 

 exposed may not faiiiy reveal the true 

 position of the strata. 



Lf those rock tracts which are un- 

 doubtedly faulted be neglected, in the 

 other places the strike and dip of the 

 rocks of both series appear very similar. 



Ai'gillaceous rocks may he much more 

 broken up and displaced by favilts than, 

 others of the same group which are 

 arenaceous. 



Fossils of Caradoc-Bala type occur in 

 some zones of the Irish Silurians of 

 Keny, Galway, and Mayo ; and there- 

 fore the occuiTcnce of such is not con- 

 clusive e^ddence in Ireland that the 

 strata containing them are Cambro- 

 Silurian. 



It is possible that the rocks of the 

 " Lower Old Eed Sandstone" type may 

 be in part equivalents of the Glengariff 

 grits, that is, of the "Passage beds" 

 between the Silurian and Carboniferous. 

 In such case it would be possible that 

 although the rocks form a continuous 

 sequence at Pomeroy, yet elsewhere, on 

 account of an overlap, higher or later 

 beds might lie imconfonnably on the 

 Lisbellaw rocks. 



The balance of the evidence was considered by us to be favourable 

 to the unconformability between the rocks of the Pomeroy series and 



2E2 



