172 JOURNAL OF THE GEOLOGICAL SOCIETY OF DUBLIN. 
and grit runs nearly east and west; the latter dips south, at from 
20° to 30°, and rests conformably on the trap, about one mile east of 
Clydagh Bridge; in the bed of the river another junction is seen, but 
the bedding of the rocks is not clear. 
The trap is not seen any further to the east. It extends to the 
north as far as Rodgers’ Rock, which is about one mile due south of 
the western summit of the Paps; here it appears to be bedded 
nearly horizontal. 
It preserves the character of either brown or green compact fel- 
stone, with pink flakes. South-west of Rodgers’ Rock, the mountain 
is covered with heather, the trap being seen only here and there in 
irregular masses. 
The length of this mass of trap, from the place first described 
near the road, to Rodgers’ Rock, in a straight line, is nearly three 
miles. 
NOTE TO MR, FOOT’S PAPER, BY MR, J. BEETE JUKES. 
The felstone traps discovered by Mr. Foot in the green and purple 
grits and slates, forming the lower part of the Old Red Sandstone near 
Killarney, perfectly resemble, in every lithological character, those 
to be seen in the lower Silurian rocks of Wales, and the S. E. of 
Ireland. The same may be said of those found by Mr. Kinahan in 
the upper Old Red Sandstone and Carboniferous Slate near Castle- 
ton, Berehaven, where, however, they are associated with green¬ 
stones, which are almost, if not entirely, absent near Killarney. 
The principal varieties of felstone near Killarney are the follow¬ 
ing:— 
1. The most abundant, a smooth, compact, siliceo-felspathic paste, 
generally of a pale-greenish or bluish-gray colour, very slightly 
translucent at the edges. This is the character of the columnar 
portion of the trap. It is frequently marked, though not in the 
columnar part, both externally and internally, by fine wavy lines or 
striae, of slightly different shades of tint from the mass, often greatly 
curved or twisted; these remind one of the striae to be seen in a 
slag from an iron furnace, as they vary solely in colour, and not in 
texture. There is no further separation of particles in this variety 
beyond the appearance of a little shining facet of a crystal of fels¬ 
par, to be occasionally discerned on turning about a fresh fracture 
variously to the light. The nodular, concretionary structure men- 
