14 
PROCEEDINGS OF SOCIETIES. 
comparison of notes, each, though agreeing as to their identity, might 
find them chameleon-like, constantly eluding his grasp ; till an umpire, 
arriving from a recent examination of the northern or Pomeroy strata, 
might decide in favour of the first, or perhaps, equally undecided with 
both, might offer a new and independent solution. In the absence of 
fossiliferous evidence, however, I fear we must quietly await the slow 
accumulation of demonstrative facts. • 
I cannot here pass over a fact which seems to me to he of importance 
in the consideration of the question before us, and that is the interstra- 
tification with the Glengarriff grits, in common with the schistose Silu¬ 
rians of the east of Ireland, as well as with those of Wales (even though 
these latter he of lower or Camhro-Silurian age), of the ash beds of Sir 
H. l5e la Beche, and of the felstone of Mr. Jukes. These, I believe, are 
not only identical in lithological character,* but are also referrible to one, 
extended, no doubt, hut still one period of igneous action, in which 
opinion I am happy to find that my friend Professor Haughton fully 
concurs; and if so, will it not follow from the theory of their contempo¬ 
raneous origin with the aqueous rocks, with which they are interstra- 
tified,—even though a lengthened period may have intervened between 
the formation of the upper and lower igneous beds,—that the Silurian 
rocks across the country, with which I would connect the Glengarriff 
grits, are also attributable to one extended epoch of sedimentary action, 
even though a similar lengthened period may have intervened between 
the deposition of the upper and lower, or Camhro-strata ; their separa¬ 
tion from unconformity not having been hitherto ascertained by any ob¬ 
servations made in Ireland. 
In conclusion, I can only say that the principal object which I have had 
in view in bringing this communication before the Society >fas for the 
purpose of assisting a discussion by which we might arrive at some rea- 
sonble and satisfactory conclusion in regard to a question which I consider 
to be of the utmost importance in the advancement of our science, and 
in which Irish geologists are especially interested. 
Professor Haughton stated that in the course of his investigations, both 
in England and Ireland, as well as on the Continent, he had had ample 
opportunities of judging of Mr. Griffith’s general views, and he had long 
coincided with his subdivision of the Carboniferous System, having paid 
much attention to the plants which had been alluded to, and he was 
happy to find that most of the statements which he had published had 
been confirmed by that eminent authority, M. Brongniart. He was glad 
to find that his friend Mr. Jukes also entertained the same views, 
and he thought, with Mr. Griffith, that the derivative character of the 
Glengariff Grits was not a sufficient ground for the separation of those 
* See Professor Jukes’ note to Mr. Foot’s paper “On the Trappean Rocks in the 
neighbourhood of Killarney,” vol. vii., Proceedings of the Geological Society of Dublin, 
page 172. 
