168 Mr. R. Griffith on Mr. Weaver's Paper relative 



We may next consider the Monavoullagh conglomerate, 

 which in his map Mr. Weaver shows as an insulated tract, 

 surrounded by transition slate ; I, on the contrary, show in 

 my section a precipitous escarpment to the north, but a gra- 

 dual declivity towards the south and south-west. If Mr. 

 Weaver be correct, his conglomerate, which he represents as 

 a mountain cap, must rest unconformably on the transition 

 slate on the south as well as on the north side ; now, I posi- 

 tively assert that such is not the fact, but that the alternating 

 series of red clayslate and conglomerate, which presents so 

 striking an escarpment on the north face of the mountain 

 range, forms the lower part of the red slate series, and that pro- 

 ceeding from the summit of Crotty's rock to the southward we 

 regularly ascend in the series, till at length in approaching 

 the Blackwater near Lismore, we meet the yellow sandstone 

 with calamites, which in so many localities alternates with the 

 carboniferous limestone, that I have been induced to consider 

 it rather as the lowest member of the carboniferous limestone 

 than the upper part of the old red sandstone series*. Now 

 if I am right in this position, what becomes of Mr. Weaver's 

 mountain cap, or of the occurrence of the old transition slate 

 to the southward of the Monavoullagh mountains ? As an ad- 

 ditional proof of the correctness of my views on the subject, 

 I have made a careful examination of the district within the 

 last month, and have prepared a plan which has been con- 

 structed with great care, and which, I think, will set the 

 matter at rest. 



The plan represents that portion of the county of Water- 

 ford extending from Ballyvoil Head in a western direction, 

 along the valley of the Ballyvoil river to Gloundolgan, a di- 

 stance of four miles, and southward from thence to Dungar- 

 van. In this district we have the unconformable outgoing of 

 the conglomerate of the Monavoullagh mountains, extending in 

 an eastern direction without interruption to the coast at Bally- 

 voil Head. Now Mr. Weaver states f in his paper, "that 

 there is no apparent connexion whatever between the horizon- 

 tal sandstone and conglomerate of the Monavoullagh range 

 and those beds of conglomerate and red slate of the coast 

 which continue eastward from Dungarvan in several separate 

 discontinuous bands interstratified with the other transition 

 rocks." In opposition to this opinion, I beg to state, that the 

 alternating strata of red clayslate and conglomerate of the 

 Monavoullagh escarpment, does extend uninterruptedly from 

 Crotty's rock to the shore at Ballyvoil Head, where they rest 

 equally in an unconformable position on the transition slate. 



* See Lond. and Ed. Phil. Mag. for March, 1840, p. 173. 

 t See Lond. and Ed. Phil. Mag. for April, 1840, p. 279. 



