Chap. VIII.] LOWEE PALAEOZOIC ROCKS OF IRELAND. 
175 
anything like a sequence of order. Still the fossils, together with the 
physical characters of the rocks, clearly mark the Lower Silurian era. In 
the cliffs on the hanks of the Eiver Suir, below Waterford, and in the 
coast headlands of Newtown near Tramore, and of Bon Mahon*, the 
schists with feeble impure concretionary limestones are underlain by 
schists which at Waterford are probably of Llandeilo age, the fossili- 
ferous beds on the coast being rather referable to the Caradoc forma- 
tion. These strata are charged with the simple -plaited Orthidse, Tri- 
lobites of the genera Trinucleus, Ogygia, and Phacops, Double Grapto- 
lites (Diplograpsus), and Corals, in as great abundance as in strata of the 
same age in Wales and Scandinavia. 
In the western districts of Cork and Kerry, I satisfied myself, by 
two visits, that the masses of hard, purple and greenish grits and slaty 
rocks which rise into the loftiest mountains of Ireland around the Lakes 
of Killarney (Macgillycuddy's Eeeks, Mangerton, &c), and range to the 
Island of Yalentia, are all of Devonian age. This is proved by the fact 
that in the promontory of the Dingle these rocks distinctly overlie and 
pass down into strata charged with true Upper Silurian fossils. Many 
of these organic remains had indeed long been known, some of them 
having been figured and described by M'Coy from the collections of Sir 
E. Griffith, with whom I first visited the district in 1842. 
At that time, however, the exact order of the rocks occupying the great 
mountainous mass of land lying between the Bays of Dingle and Tralee had 
been little examined. Still, even then, Professor Phillips and myself had 
come to the conclusion that a great portion of these mountains must belong to 
the Devonian system, since it was evident, even on a first traverse, that these 
strata rose up from beneath the lowest Carboniferous Slate and Limestone. 
The nomenclature which Sir E. Griffith was formerly induced to adopt 
respecting these south-western tracts, though now changed, was very ra- 
tional. Seeing vast masses of chloritic and quartzose schists and other 
bands of very ancient -looking rocks that were in certain tracts uncon- 
formably surmounted by red conglomerates and sandstones, which latter 
he knew to be inferior to everything Carboniferous, that vigilant and 
indefatigable observer naturally grouped the first-mentioned of these as 
Silurian, and so at first coloured them in his excellent Geological Map of 
Ireland. 
Now a chief portion of the rocks which Griffith termed Silurian were 
those mountain-masses which are splendidly exhibited near Glengariff, and 
roll over in the lofty undulations around the Lake of Killarney before 
_ * Most of the fossils described by Mr. Weaver Griffith and his assistant, Mr. John Kelly, to be Si- 
m his memoir on the South of Ireland, Trans, lurian, though with no precise reference to their 
breol. Soc. Lond., 2nd ser., vol. v. p. 1 et seq., are age. In the public collection in Stephen's Green, 
now known to pertain to the Carboniferous Dublin, and in the rich cabinet of Sir E. Griffith, 
system ; but certain localities which he notices, the geologist will find an instructive assemblage 
such as Smerwick Harbour or Ferriter's Cove, of these Lower Silurian fCaradoc) fossils of 
and Bon Mahon, near Waterford, which he termed Waterford. 
' transition,' were long ago recognized by Sir E. 
