XI.—ON THE RELATIONS OF THE CARBONIFEROUS, DEVONIAN, AND 
UPPER SILURIAN ROCKS OF THE: SOUTH OF IRELAND TO 
THOSE OF NORTH DEVON. By EDWARD HULL, m.a., u1.p., F.R.s., 
Director of the Geological Survey of Ireland, and Professor of Geology, Royal 
College of Science, Dublin. With Prarus IV. and V., and Wooncuts. 
[Read November 17th, 1879. | 
My subject appears to divide itself into two heads—Ist, the geological age of the 
great group of rocks which forms the main portion of the southern highlands of 
Treland, namely, “the Dingle or Glengariff Beds” ; and 2nd, the relation which these 
and the overlying formations in the south of Ireland bear to those of North Devon. 
And having discussed these questions, I shall conclude this paper with an attempt 
to describe the palseo-physical geography of these districts, as indicated by the 
relations of the formations respectively. 
I.—Composition and Geological Age of the Dingle or Glengariff Beds. 
The rocks which rise into the highest elevations in the south-west of Ireland, 
both to the north and south of Dingle Bay, belong to the same great group to 
which the late Professor Jukes applied the names of ‘“ Dingle beds,” or ‘‘ Glengariff 
grits and slates.” Although the lowest beds of the group which occur in the Dingle 
promontory do not appear to reach the surface amongst the mountain ranges which 
rise to the south of Dingle Bay, yet there is no necessity that two names should, on 
this acount, be applied to the same general group of strata; I therefore propose 
in this paper to designate the group by the name of “ Glengariff beds” only, a name 
derived from that bold and rugged ridge which lies between Kenmare and Bantry 
Bays, in which these beds are well represented. 
(a.) Composition of the Glengariff Beds.—The nature and composition of this 
great group has been so often described by previous writers that a brief account is 
all that is necessary here. Taken asa whole, it consists of three principal divisions, 
as follows :— 
1. Upper. — Consisting of purple slates with bands of grit, and a fossiliferous conglomerate near the 
top (“ Parkmore Point conglomerate ”). 
2. Middle.—Consisting of massive green and purple grits, sometimes pebbly, and containing slaty 
and calcareous bands at intervals. 
3. Lower. — Consisting of purple and variegated slates and flagstones, resting conformably at Dingle 
upon fossiliferous beds of Upper Silurian age. 
The thickness of the whole of this great group of rocks may be taken at about 
10,000 feet. They appear to be unfossiliferous, except for the occurrence of linear 
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