712 PROF, E. HULL ON THE DINGLE BEDS AND 
of Cork, Tipperary, and Waterford attains to important vertical 
dimensions, is entirely absent ; consequently there can be no passage 
from the Glengariff grits and slates into the Carboniferous beds. 
Unconformable overlap upon the Glengariff Beds. 
A detailed examination of the working maps of the 8. W. of Ireland, 
carried out with the assistance of Mr. A. M‘Henry, has developed 
the following remarkable results bearing upon the past and present 
relations of the Glengariff series to the Old Red Sandstone and Car- 
boniferous beds, proving beyond question their unconformity here 
as well as in the Dingle promontory. If we take a series of trans- 
verse sections along a line drawn from the extreme 8.W. of Cork or 
Kerry to the N.E. near the border of Cork and Waterford, the fol- 
lowing will be found to be the relative positions of these beds, as 
illustrated by the diagrams (figs. 5-8). 
Fig. 5 shows these relations diagrammatically and in plan. It 
will be observed that at the extreme left, or S.W. direction, in the 
district of Dunmanus, Bantry, and Glengariff Bays, the Lower Car- 
boniferous slate (1) rests directly upon, or against, the Glengariff 
beds (5). In the centre the overlap is not so great, as the Yellow 
Sandstone (2) rests directly upon, or against, the Glengariff beds 
(5); and at the extreme right or N.E. direction, in the district 
between Cork and Mallow, the overlap is still less, for the Old 
Red Sandstone and Conglomerate (3, 4) rests directly upon or 
against the Glengariff beds. These relations are still further ilus- 
trated in the three transverse sections (figs. 6, 7, and 8). Hence it 
will be observed that while the formations 1, 2, 3, and 4 are every- 
where conformable to each other, they are everywhere unconformable 
to No. 5. There has, therefore, been a deeper depression towards 
the south-west of the old land-surface formed by the Glengariff 
beds, or a subsequent greater elevation and denudation towards the 
north-east after the Carboniferous period. The case of the S.W. of 
Ireland is somewhat comparable to that of the overlap of the Upper 
Silurian upon the Cambrian beds from Herefordshire towards the 
Longmynds*. 
Note.—The view of the relations of the beds above given has 
since been abundantly confirmed by the detailed re-survey of the 
Cork district by Mr. M‘Henry during the past summer (1879). 
III. Comparison wit Srcrions in GAtway AND Mayo. 
If any further evidence regarding the age of the Dingle beds than 
that already adduced were required, it would be found in a comparison 
with the Upper Silurian rocks on the banks of Killary Harbour in West 
Galway and Mayo. Here we find precisely similar beds, sufficiently 
* As I have endeayoured to show elsewhere (Geol. Mag., Dec. 1878), I be- 
lieve this region to have been a land-surface or shoal water during the deposition 
of the marine Devonian beds of Deyonshire and the Rhine; nor was it resub- 
merged till towards the uppermost Devonian period. In this view, lam happy 
to say, Mr. A. Champernowne concurs (Geol. Mag., March 1879). To this sub- 
ject I purpose on another occasion to return. 
