44 REPORT—1843. 
These strata are followed by others very similar in character, excepting that the 
sandstone rather predominates: near the base, in the lands of Formil, close to the 
village of Kesh, a bed of highly carbonaceous shale with two inches of bituminous 
coal occurs in the sandstone. The shales produce the same Modiolas, Pectens, &c. 
as those lower in the series; but on the lands of Drumcurren, on the left bank of the 
river Banagh, numerous perfect casts of the scales of the Holoptychius Portlockii, 
accompanied by a single specimen of a tooth of the Chomatodus linearis ; also plants 
identical with those of Kilcummin Head, particularly the Sphenopteris, and a small- 
leaved plant, apparently a Fucoid. 
Above the fish-scales, and approaching the great or lower limestone, the shales 
were found to contain Fenestellz, accompanied by Turbinolia, &c., indicative of the 
carboniferous slate, but owing to the unusual abundance of sandstone which accom- 
panies the shale, it is impossible in this locality to draw the line of separation between 
the carboniferous slate or lower limestone shale and the yellow sandstone ; the thick- 
ness of this upper portion of the series may be about 1200 feet, thus making the 
whole series, including the yellow sandstone and carboniferous slate, about 2900 
feet in thickness. The carboniferous slate is succeeded by the lower limestone, 
the thickness being about 700 feet, and this again by the calp shale and calp 
sandstone. 
Near Lisnarick, in the line of section, the calp series rests unconformably on 
brownish-red conglomerate, forming a portion of the great district, chiefly composed 
of alternations of that rock and brown micaceous shale and sandstone slate, which 
occupies considerable portions of the counties of Fermanagh and Tyrone, and which 
in two localities, as at Pomeroy and Lisbellaw, is connected with rocks belonging to 
the Silurian system. 
In the line of section this series occupies a tract of country extending from Lisna- 
rick on the west to Lisbellaw on the east, a distance of fourteen miles. At Lisbellaw 
the Silurian rocks are suceeeded unconformably by strata belonging to the yellow 
sandstone series, which is here very imperfectly developed, owing probably to its 
being cut through by the projection through it of the Silurian and brown sandstone 
series. The yellow sandstone is followed by the carboniferous slate, and this again 
by the lower limestone, and in continuation by the calp, and calp sandstone of the 
Slievebeagh mountains, from beneath which in an eastern direction we find the lower 
limestone and carboniferous slate, appearing at the surface in the valley of Monaghan, 
and terminating unconformably on the greywacke slate which bounds that valley to 
the south-east. 
The most important part of this section, as far as the lower members of the car- 
boniferous series are concerned, is that situated to the west of the brownish-red con- 
glomerate district. In it we find the same succession of strata which have already 
been discovered as occurring on the north coast of Mayo: we have the same alterna- 
tions of sandstones, shales, and impure limestone at the base, succeeded by shales and 
sandstones and thin beds of limestone, each part of the series producing the same 
fossils ; the limestone beds, whether arenaceous or argillaceous, containing those 
which belong to the upper portions of the limestone series ; while the shales which 
lie below, among, and above the arenaceous limestone, contain the same fossils, the 
most characteristic being Modiola Macadami, the most remarkable the scales of the 
Holoptychius Portlockii, and of the plants the Sphenopteris and the smooth-leaved 
Fucoid ; hence no doubt can be entertained of the necessity of including both in one - 
series, the whole being followed by the great or lower limestone. 
A remarkable and extensive district of yellow sandstone occupies the whole of the 
southern shore of Lough Foyle in the county of Londonderry, between the city of 
Derry and the basaltic headland of Magilligan, from whence it extends southward to 
Dungiven, and thence by Draperstown to the base of Slieve Gallion mountain in the 
county of Londonderry. The strata in this district are divisible into three portions. 
The lowest is characterized by its conglomeritic structure and the absence of shale or 
calcareous matter. The colour of the base of the rock is usually red. The pebbles, 
or rolled fragments of the lower beds, consist of mica-slate, similar to the rock on 
which it rests, and the upper of white quartz, and occasionally of red quartzose 
sandstone. These strata in the Douglas river, near Draperstown, may amount to a 
thickness of 600 feet. The second division of the series is distinguished by its con- 
taining numerous beds of dark gray shale approaching to black, alternating with gray — 
