118 
JOURNAL OF THE GEOLOGICAL SOCIETY OF DUBLIN. 
clay slate, interstratified with gray grit beds, the old grauwacke 
series, which includes both Cambrian and Silurian rocks, but it 
sometimes rests on other rocks, as I shall show. 
To point out more clearly some of the facts supporting the 
views I take, I have drawn up the following Table, which shows in 
several localities the dip of the supporting rock near the junction, 
and the unconformable dip of the sandstone, as set out in the head¬ 
ings of the columns. It rarely happens that a good junction with 
the two kinds of rock can be seen; but in the greater number of 
cases the observations are made within a short distance of each 
other, and since the beds of the Carboniferous formation through¬ 
out are parallel to one another, two different rocks, visible at spots, 
even a furlong distant, can be known to be conformable or other¬ 
wise, where no sign of undulation or disturbance is visible in the 
vicinity. I begin with the northern counties, and proceed south¬ 
ward :— 
