86 
THE GEOLOGIST. 
tains, is about 5 miles from N.W. to S.E., with an average width of 
about 1 mile at Kilronan mountain, which forms the eastern termina- 
tion of that long narrow coal-measure basin. The Altagowlan basin, 
on the oppo^ite side of tlie Arigna valley, may be about 3 miles, from 
N.W. to S.E., with a width of three-quarters of a mile. In these 
areas there are but three beds of workable coal, the thickest of 
which is not over 2 feet 6 inches, and one of the beds has its roof and 
floor of hard sandstone. See "upper coal seam of Creughnaslieve." 
The following is Sir E. GriflBth's section of the Kilronan Mount 
coal-measures, taken from his ' Mining Eeport on the Connaught 
Coal-fields,' and its general accuracy is undoubted : — 
Strata. 
Feet. 1 
Surface 
18 
30 to 50 
Sandstone tiags. 
17 
30 to 60 
Blackish-grey sandstones and iiritty slate. 
16 
100 to 200 
Slate clay, in beds of variable thickness and hardness, and con- 
taining innumerable beds of clay ironstone. 
15 
Coal. 
Third or upper seam, 8 to 9 inches thick (?). 
14 
24 to 45 
"White sandstone. 
13 
10 to 15 
Grey soft slate clay. Coal roof. 
12 
Coal. 
Second coal, 2 ft. 6 in. to 3 ft. 4 in. (Over-estimated.) 
11 
12 to 15 
Sandstone. 
10 
6 to 15 
Black slate clay. 
9 
4 to 20 
Greyish-white sandstone. 
8 
Coal. 
Third or " Crow " coal, intermingled with clay lamina;, 1 to 3 
feet. (Over-estimated.) 
7 
1 to 3 
Fire clay. Coal seat. (Over-estimated.) 
6 
1 to 3 
Sandstone, with plant impressions. (Often much thicker.) 
5 
6 to 10 
Grey (and very hard) sandstone. 
4 
9 to 20 
Black slate clay (shale). 
3 
30 to 60 
Greyish-white sandstone, known as the first or bottom sand- 
stone.* 
2 
300 to 600 
Black slate clay, with grey flags, and innumerable ironstone 
nodular layers and beds, varying from half an inch to 2 feet 
in thickness. t 
1 
Carboniferous limestone, unknown. Page 20 of Report. 
As my examination of these coals was confined to the Arigna dis- 
trict, and had distinct reference to those places where coal is now 
being raised, I shall limit my remarks to the facts which came 
under my own observation, as by so doing I shall afford some aid to 
future explorers in this most interesting and important field of 
research, and I cannot prejudice the question as to the advisability 
of these beds being worked as a profitable mining speculation. 
* Upwards of 250 feet thick at Altagowlan, and close on 200 feet on the south-east 
flank of Kilronan. 
t Upwards of 800 feet at .Vlttigowlaii mouulain. 
