280 Mr. Weaver 07 i the Structure of the South of Ireland^ 
(putting my own descriptions out of the question), he must 
have seen that Mr. Holdsw'orth 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 Monavoullagh 
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 westw^ard 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 Monavoullagh range of conglomerate 
on the north ; and Mr. Holdsworth observes*, that in this 
part the base of the Monavoullagh mountain range approaches 
close upon the clayslate formation. With respect to the 
Monavoullagh conglomerate itself, he remarks •f, 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 now^here 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 Monavoullagh range. Mr. Holdsworth, in 
concluding, touches upon the question as to the source and 
origin of the conglomerate range of the Monavoullagh 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 p. 97. 
