592 Scientific Proceedings, Royal Dublin Society. 
received the newer deposits to have been approximately flat, a 
bed oblique to that surface, making therewith so small an angle 
as 5°, would at ten miles distance as the angle opened be separated 
from its basement by nearly a mile in thickness of rocks, almost 
certainly sufficient to have afforded some stratigraphic difference 
of aspect, that would force the discordance upon the attention of 
an observer of the various sections exposed in the country. 
But if two sets of beds are in such exactly parallel relation 
over wide areas as to exhibit the same junction features and with 
any appearance of transition, how, in the absence of such crucial 
tests as definitely recognizable layers occurring in the sections, 
is discordance to be proved, and if necessarily present might it 
not as well be situated in any part of the Dingle-Glengariff series 
as at the top. 
Unless the supply of rock-forming sediments had been every- 
where equally maintained, and equally distributed under immu- 
table conditions, must not aJl sedimentary beds, groups, and for- 
mations thin out or overlap, in the manner shown by Professor 
Hull’s diagrams, even without the existence of a break equal to 
discordance in the succession ? 
2. The total area of the country now referred to, would be in- 
cluded within a square of sixty or seventy miles on the side. 
The distance from Dingle to Iveragh across Dingle Bay is about 
ten miles. The Lower Carboniferous rocks southwards have been 
denuded so as to remain visible only at a distance of some sixteen 
miles further to the south, so that they are now thirty-six miles 
from the Dingle country. But if all the folds of Iveragh and 
those beneath Dingle Bay, were reduced again to approximate 
horizontality, the distance would doubtless be greater by several 
miles. Is it not within the limits of possibility that this distance 
may have been sufficient for the Old Red beds of the Dingle 
type—a shore deposit—to have died out towards Kenmare estuary, 
or changed in their composition so as to be no longer recognizable 
as lithologically the same. 
It seems to me there are many cases 1n which rocks change 
their character entirely on the same horizon, at a distance of 
thirty to forty miles, but the point would of course only be urged 
as possibly collateral negative evidence in the absence of positive 
testimony to the contrary. 
