RESEARCHES AMONG THE PALAEOZOIC ROCKS OF IRELAND. 141 
In the lower Devonian, as given in the Table, the gray sandstones 
of Caithness, and the green chloritic schists of Cornwall, are of a 
colour and kind that I never saw in the Old Red Sandstone of 
Ireland. 
It is much to be regretted that Sir C. Lyell has not supplied 
even an ideal cut to show how he joins the Old Red Sandstone to 
the underlying rocks. Such a cut would show something relating 
to the conformability of the groups, which the verbal Table does 
not express. 
In the diagram, which I exhibit, let the upper part with hori¬ 
zontal strata represent the Carboniferous formation, with its three 
subdivisions—-coal, limestone, and red sandstone; and let AB be 
the base of the latter, the conglomerate bed, laid unconformably 
on the inclined ends of the underlying strata, as a foundation. 
Those strata, as I have shown, are of many kinds. In the seventy- 
eight localities I have pointed out, the conglomerate lies on fourteen 
different kinds of older rocks. Let a represent granite; A, strati¬ 
fied quartz rock; c, mica slate; d, primary crystalline limestone; 
e, greenstone; /, amorphous quartz rock; g , gray clay slate; A, gray 
grit; i, red clay slate; A, green grit; l, green chloritic slate; m, 
brownstone. 
Now cut away the Old Red Sandstone from the Carboniferous 
formation, and let it go to the underlying rocks; then take of these 
rocks a horizontal band 1000 feet in thickness, to represent the re¬ 
mainder of the Devonian. It is plain, then, that in Ireland this 
formation will be represented by its upper part, the Old Red; and 
below, by portions of all those other older rocks; and, therefore, 
that all the older stratified rocks in Ireland take a share in the De¬ 
vonian system, as well as some of the igneous. 
This is my view of the Devonian system. Had it been composed 
of a regular succession of rocks, lying together like the Silurian 
system, or like the Carboniferous formation, there would be no 
doubt about it; but to make it good, instead of working it out in 
Devon, its own country, one of the most profound geologists found 
it necessary to ransack Europe, to get suitable parts to make it up; 
and it appears to me that Sir Charles Lyell undertook no easy task 
when he took a limb from Dura Denn, a joint from the cornstones 
of Herefordshire, an arm from the green chloritic slates of Corn¬ 
wall, a leg from the gray sandstones of Cromarty, and a part from 
