280 Mr. Weaver on the Structure of the South of Ireland, 



(putting my own descriptions out of the question), he must 

 have seen that Mr. Holdsworth places in the map and speaks 

 in the text of the clayslate formation, as being observable in 

 different places along the eastern border of the MonavouUagh 

 range of conglomerate ; and especially as being of consider- 

 able extent in the vicinity of Stradbally, where it is in a highly- 

 inclined position, and in places nearly vertical, stretching 

 thence to the westward toward the vale of Dungarvan, and 

 there coming in contact with the carboniferous limestone of 

 that valley* In its range, therefore, the clayslate formation 

 evidently occupies the district lying between Ballyvoil head 

 on the south and the MonavouUagh range of conglomerate 

 on the north ; and Mr. Holdsworth observes*, that in this 

 part the base of the MonavouUagh mountain range approaches 

 close upon the clayslate formation. With respect to the 

 MonavouUagh conglomerate itself, he remarkst, that having 

 examined this mountain range in several places along its 

 line from north to south (which extends many miles), and 

 from top to bottom, it nowhere appeared as a conformable 

 rock. Now, let us return to the coast, stretching eastward 

 from Ballyvoil Head. What is the purport of Mr. Holds- 

 worth's observations in this quarter, and more inland, in re- 

 ference to the occurrence of red sandstone conglomerate and 

 red slate as forming beds included in the clayslate formation ? 

 He says, that in various places along this line of coast, and 

 particularly around Bonmahon, he met with the conglomerate 

 usually accompanied by red micaceous slate, both being in an 

 inclined position, and having the appearance of being a con- 

 formable formation, inasmuch as these strata, where they 

 occur, appear bounded on each side by the common rocks of 

 the coast. And the conglomerate is described as being both 

 coarse and fine-grained, the latter passing by insensible gra- 

 dations into the red sandstone slate; and a coarse sandstone 

 with ferruginous marks also occurring. The red sandstone 

 slate passes, he says, sometimes into grey slate, portions of 

 which occur abundantly in the composition of the conglo- 

 merate of the MonavouUagh range. Mr. Holdsworth, in 

 concluding, touches upon the question as to the source and 

 origin of the conglomerate range of the MonavouUagh and 

 those beds of conglomerate which are conformably associated 

 with the common rocks of the coast and in the interior, 

 which latter he also terms, "detached dyke-like masses;" and 

 he inquires whether they may have been contemporaneously 



* Journal of Geol. Soc. of Dublin, vol. i., part 2, p. 89. f Ibid., p. 97. 



