716 PROF. E. HULL ON THE DINGLE BEDS AND 
the throat of the old voleanic vent, from which were blown out the 
fragmental materials above described. 
These volcanic beds reappear along the southern shore of Clogher 
Bay, and in the adjacent islands, Beginish, Young Island, and Inish- 
vickillane *. 
The representative volcanic beds in the region of the Killarney 
mountains are included in the Glengariff-grit series, and therefore 
belong to a somewhat later stage than those laid open along the 
Dingle coast. These beds range through a distance of about ten 
miles from east to west, entering into the structure of the rugged 
elevations above Lough Guitane, and the slopes of Mangerton, Car- 
rigwadra, and Killeen, north of the river Clydagh. These volcanic 
products consist of felstone, felstone porphyry, and beds of ashes and 
agglomerate, interstratified with the sedimentary slates and grits 
among which they are enclosed. 
One of the principal vents of eruption was situated about a mile 
south of Lough Guitane, and is represented by the bold and sombre 
mass of Benaunmore. This rock consists of columnar light green fel- 
stone, with crystals of felspar thinly disseminated. Itis traversed by 
several dykes of yellowish and pale pink felstone, and on either side 
beds of felspathic ash interstratified with the slate of the district. 
Mr. Du Noyer considers the ash-beds to bear evidence of aqueous 
depositiont. As illustrating the general character of these volcanic 
rocks, the following section (fig. 10) made by the writer and Mr. 
M‘Henry on the hills of the Flesk valley, will probably be useful and 
sufficient. It will be seen, on referring to Fig. 9, that similar vol- 
canic products occur among the Mweelrea beds. 
Fig. 10.—Section of Volcanic Beds in the Hills west of the River Flesk 
near Lough Athoonyastooka. (Length of section about 600 
yards.) 
1. Green grits, &e. 5. Purple slate. 
2. Purple felstone porphyry. 6. Beds of ash, cleaved. 
3. Purple slate. 7. Purple slate. : 
4, Beds of fine ash, cleaved. x Felstone porphyry, either a dyke 
or a volcanic neck. 
* See Geol. Survey Map, sheet 171, and “Explanation ” thereto. _ 
+ “Explanation ” sheet 184, p. 15. Prof. A. von Lasaulx, who, with Prof. F. 
Romer, visited this district in 1876, gives a graphic description of these rocks 
as they occur on the flanks of Mangerton, in ‘ Aus Irland,’ p. 81 e¢ seg. 
