GLENGARIFF GRITS AND SLATES. TOL 
1867. Prof. Jukes, in a paper comparing the rocks of the South- 
west of Ireland with those of Devonshire, admits that the Dingle 
beds seem to be physically more connected with the Upper Silurian 
than with the Old Red Sandstone*. 
In this year also Sir Roderick Murchison, in the fourth edition 
of ‘ Siluria’ (p. 178), after describing the conformable upward pas- 
sage of the Dingle beds with Silurian fossils into the “ Glengariff 
grits and schists,” maintains that the latter represent ‘those slates 
and grits which in Germany, Belgium, and North Devon form the 
lowest portion of the Devonian system.” 
In the maps and explanatory Memoirs of the Geological Survey 
of Ireland the “ Glengariff grits and slates,” which are the represen- 
tatives of the “ Dingle beds,” are coloured and described as Old Red 
Sandstone; but in the Dingle promontory these beds are separated 
from the Old Red Sandstone, and are coloured reddish brown. This 
is explained by Prof. Jukes to be due to the fact that while the 
boundary line of the ‘“ Dingle beds” is quite distinct in the Dingle 
promontory, it was found impossible to draw any corresponding line 
elsewhere. He “therefore thought it best not to prejudge the 
question.” 
Il. REEXAMINATION OF THE SECTIONS. 
From the above abstracts and notices of authors it will be seen 
that the opinions regarding the age of the Glengariff grit and slate 
series are various. We might almost say “ quot homines tot sententiw.” 
All are agreed that the beds form a group intermediate between Old 
Red Sandstone above and Upper Silurian beds below; by some 
authorities they are classed with the Upper Silurian, by others with 
the Devonian, by others with the Lower Old Red Sandstone. Be it 
recollected, however, that as far back as 1839 the late Sir Richard 
Griffith expressed his opinion that this series, together with the 
subjacent fossiliferous Silurian beds, would eventually prove to 
be of Silurian age. This view he subsequently illustrated and en- 
forced ; and Prof. Jukes admits that “ theoretically it is the better of 
the two” alternatives between Silurian and Old Red Sandstone. 
I have never been able to understand exactly why it has been 
departed from by other observers. For myself, I not only concur 
in this view upon the grounds which he has advanced, but I hope 
to be able to adduce in this paper evidence additional to any yet 
offered in its favour. 
The question having been confessedly left an open one by my 
predecessor, and subject to further investigation, I obtained the 
permission of the Directer-General to reexamine the sections in 
Kerry and Cork likely to throw light upon it; and in company with 
Messrs. J. O’Kelly, Senior Geologist, and Mr. A. M‘Henry, Assistant 
Geologist, I made a tour of the district during the month of 
September 1878. 
We first visited the sections in the Dingle promontory+, then 
* Journ. Roy. Geol. Soe. Irel. vol. i. p, 105 (1867). 
t In this first district Mr. M‘Henry was my only -companion, as Mr, 
O'Kelly did not join us till we reached Killarney. 
Q.J.G.8. No. 140. 3B 
