720 PROF. E. HULL ON THE DINGLE BEDS AND 
it becomes attenuated, and ultimately terminates against the flanks 
of the old granite ridge, where it is conformably overlapped and dis- 
appears beneath the Carboniferous Limestone, which, in turn, abuts 
on the same granitic ridge at Gores Bridge. 
Throughout this tract the Old Red Sandstone consists of dull, 
reddish-brown, rather soft sandstone, often pebbly, and sometimes 
supported by thick masses of breccia and conglomerate of quartz, 
jasper, trap, and Lower Silurian grit. The upper beds contain bands 
of reddish shale, and the whole series attains in Co. Waterford a 
thickness of about 3200 feet*. ‘The formation, indeed, in its usual 
condition, bears a strong resemblance to the ‘“‘ Pebble-beds” of the 
New Red Sandstone of Lancashire and Cheshire ; and, on the other 
hand, has but a faint resemblance to the “‘ Dingle beds” and Glen- 
gariff-erit series.” The contrast has long ago been pointed out by 
the late Mr. John Kelly, F.G.S., in the following passage, which I 
quote in preference to using language of my own :— 
“The Old Red Sandstone has two prominent points of character 
which, in all parts of Ireland, stand out in relief and make it a rock 
which cannot be mistaken for any other. The first is a thick band of 
conglomerate at its base, which generally contains quartz, jasper, and 
other pebbles. The second that this conglomerate always lies uncon- 
formably on the inferior rock. The other characteristics are that the 
lower part of it is usually of a red colour; it passes upwards into 
yellow ; but both are comparatively soft, and easily split for economic 
use into rudely rectangular blocks, a circumstance quite at variance 
with, and distinguishing it from, the Silurian grits [meaning Glen- 
gariff grits, &c.], which are so much affected by cleavage and so 
hard, that the blocks are quite refractory under the wedge, hammer, 
or chisel, and cannot be worked satisfactorily for building-purposes”}. 
The upper portion of the formation consists of pale yellow and 
greenish sandstones and shales, sometimes containing pebbly beds, 
often rippled and flaggy, and containing remains of plants, fresh- 
water bivalves, and fish, such as Bothriolepis (Dendrodus), Coccos- 
teus, Pterichthys, Glyptolepis elegans. Paleeontologically, this is the 
most interesting and important member of the whole group, and is, 
in all probability, the equivalent of that part of the Upper Old Red of 
Scotland containing the sandstones of Dura Den, with Holoptychius 
and other fishes, to which the Yellow Sandstone of the south of Ire- 
land bears sometimes, curiously enough, a strong resemblance. 
Professor Geikie has suggested that the Dingle beds or Glengariff 
Grits may be the representatives of the ‘‘ Lower Old Red Sandstone” 
of Scotland (‘‘ Old Red Sandstone of Western Europe,” part i. Trans. 
Roy. Soe. Edinb. 1878). If this be so, then they would be the 
marine representatives of lacustrine deposits. Both are unconform- 
ably overlain by (Upper) Old Red Conglomerate and Sandstone. 
* “ Explanation ” to sheets 167, 168, &c. of the Geol. Survey Maps, p. 15. 
+ “Extracts” which were intended to beapplied to Sir R. Griffith’s Geological 
Map, published in ‘ Atlantis,’ January 1859. 
