120 PROCEEDINGS OF SOCIETIES. 



shales and sandstones of Slieve Rushen, near Swanlinbar, and the 

 country about Lough Allen, called the Connaught Coal district, and to 

 imagine them all at one time connected. No one will deny that the Coal 

 districts of Great Britain — perhaps of Europe — were deposited at the 

 same geological period, and under the same conditions. 



On this account I may here observe, that it appears to me inconsistent 

 with geological reasoning to suppose that any such great wedge of calp 

 as that described between Bundoran and Drumahaire could have been 

 deposited in one place, and no calp at all in another place, the two only 

 a few miles distant, in any such general system of deposition. 



From several considerations, I am of opinion that the Slievebeagh 

 mountains, shown on the " Map" to represent calp, are of the Coal for- 

 mation. The limestone at Monaghan dips north-west and at Clogher 

 south-east under them (see Plate VI., Fig. 6) ; thus showing that the 

 shales, sandstones, and ironstones of the Slievebeagh district rest on 

 limestone in the same way as the shales, sandstones, and ironstones of 

 the Castlecomer district does, or as the Munster and Connaught Coal 

 districts do, or, as apart of the same band does, the Coal Island district 

 near Dungannon. 



Mr. Griffith says of this locality, at par. 9, that " the district of the 

 Slievebeagh mountains has long been considered to belong to the true 

 Coal formation, and sanguine expectations have been entertained of the 

 discovery of workable beds of coal ; but having ascertained that, in the 

 order of succession, it forms a portion of the calp series, it appears very 

 improbable that these expectations will be realized." Having a theory 

 fixed in his mind that there must be a Lower and an Upper Limestone, 

 with a band of calp between them, and finding in the Slievebeagh 

 mountains that there is but one limestone, or that there is no Upper 

 Limestone, he concludes, of course, consistently with his theory, that 

 there was no coal which in position could only be found overlying that 

 Upper Limestone. 



It will be seen by reference to his " Report of the Tyrone Coal Dis- 

 trict," in the Table of '* Strata," at p. 16, that the first bed of coal is 211 

 yards above the limestone at Drumglass, near Dungannon; and he shows, 

 at p. 39, that in the immediate vicinity of Coal Island there are seven 

 workable beds of coal, amounting to 34 feet in the aggregate thickness, 

 and that all these beds are in 196 yards of thickness of the strata, from 

 the lower bed of coal to the upper, or 407 yards from the limestone to 

 the upper bed, including them all. 



At Dungannon Mr. Griffith has drawn a line across the country to 

 the north-west, marking the eastern boundary of the calp of the Slieve- 

 beagh district. On the east side of this line are limestones, shales, and 

 sandstones ; on the west side of it are similar limestones, shales, and 

 sandstones. Thus the rocks are the same on both sides of the line, and 

 there is no reason why a boundary line should be made at this point, 

 only that coal has been worked on the east side, and no coal yet disco- 

 vered on the west. 



On this part of the subject it appears to me that the limestone at 



