tone Grit and Coal Measures remain
above the limestone, extending from Mallow and Kanturk to the Limerick
and Kerry borders. Another synclinal of Carboniferous Limestone runs
from Millstreet through Lismore, and the Blackwater has worn out an
easy course along it. Then the Old Red Sandstone again rises as an
undulating upland through the centre of the county, with a few
synclinal patches of Carboniferous Shale and Limestone caught in on
its back. Cork city lies on the north slope and in the floor of a
larger synclinal, and the Yellow Sandstone, which forms the
passage-beds from the Old Red Sandstone to the Carboniferous, appears
near the city. This hollow continues across the Lee through Middleton.
The limestone in it has become crystalline, veined and brecciated,
while a fine red staining, especially at Little Island, adds to its
value as a marble. After another anticlinal of Old Red Sandstone, the
Carboniferous Slate occupies most of the country southward, with
occasional appearances of the basal Coomhola Grits and of the
underlying Old Red Sandstone along anticlinals. The soils thus vary
from sandy loams, usually on the higher ground, to stiff clays along
the limestone hollows.

This country admirably illustrates the system of river-development
originally traced out by Prof. J. B. Jukes in 1862, and further
explained by Prof. W. M. Davis and others. The folded series,
culminating originally in Upper Carboniferous strata, was worn down,
perhaps as far back as Permian times, until it possessed a fairly
uniform surface. This surface, or "peneplain," was probably the result
of denudation working away the beds almost to sea-level. A subsequent
elevation enabled the streams, as in so many cases now recognized, to
cut into the surface along the direction of greatest inclination,
which here happened to be southward. When the higher strata had been
worn away, the rivers and their tributaries worked upon rocks of very
various hardness, but with a common strike from east to west. The
tributaries, running along the strike, speedily confined themselves to
the synclinals of limestone, along which they could erode and dissolve
long valleys. The present surface of anticlinal sandstone ridges and
synclinal limestone hollows thus began to arise; but the main streams
still held on their courses across the strike, that is, from north to
south. Here and there a more