183 
those of Mayo and Galway, those of Wicklow, and 
those of Kerry. The rocks composing the four 
first of these mountain chains are principally granite, 
gneis, sienite, micaceous schist, and porphyry. The 
mountains of Kerry are chiefly constituted by gra- 
nular quartz, and chlorite schist. Coloured marble 
is found near Killarney ; and white marble on the 
western coast of Donegal. 
Limestone and sandstone are the common 
secondary rocks found south of Dublin. In Sligo, 
Roscommon, and Leitrim, limestone, sandstone, 
shale, ironstone, and bituminous coal are found. 
The secondary hills in these counties are of con- 
siderable elevation ; and many of them have basal- 
tic summits. The northern coast of Ireland is 
principally basalt; this rock commonly reposes 
upon a white limestone, containing layers of flint, 
and the same fossils as chalk; but it is considerably 
harder than that rock. There are some instances, 
in this district, in which columnar basalt is found 
above sandstone and shale, alternating with coah 
The stone-coal of Ireland is principally found in 
Kilkenny, associated with limestone and grau- 
wacke. 
It is evident from what has been said concerning 
the production of soils from rocks, that there must 
be at least as many varieties of soils as there are 
species of rocks exposed at the surface of the earth ; 
in fact there are many more. Independent of the 
changes produced by cultivation and the exertions 
of human labour, the materials of strata have been 
mixed together and transported from place to place 
by various great alterations that have taken ,plaee 
N 4f 
