48 REPORT—1843. 
Besides the trappean ash conglomerate, for such he must consider it, the district 
contains other rocks of an igneous character. Tracts occur composed of a brownish 
felspathose porphyry, apparently a metamorphic shale, or fine-grained sandstone. 
The hill called Barrack Hill, south of Pomeroy, is formed of this rock, as is also the 
hill of Millix near Ballygawly ; at this latter place it exhibits every appearance of 
having been projected through the trappean conglomerate. 
Trap dykes also occur in this district, and some of them are remarkably large, and 
can be traced for many miles along the surface. 
Connected with the strata above described and lying beneath them, apparently in 
a conformable position, there are two small districts composed of gray arenaceous and 
schistose beds, which contain numerous fossils, many of which are similar to those 
described by Mr. Murchison in his ‘ Silurian System.’ One of those districts is situated 
close to Pomeroy in Tyrone, and the other at Lisbellaw in the county Fermanagh. 
The composition and the fossils of these districts have been so lately described by 
Captain Portlock in his ‘ Geological Memoir of the County of Londonderry and por- 
tions of Tyrone and Fermanagh,’ that he would not enter upon them further than to 
state, that the upper portion of the series at Pomeroy and at Lisbellaw contains beds 
of conglomerate composed of pebbles of quartz, mica-slate, and occasionally green 
chloritic matter with a quartzose cement. This conglomerate alternates with dark 
gray shale, and in some localities with red shale and brown sandstone. 
The great mass of the reddish-brown sandstone and conglomerate lies conformably 
above the fossiliferous Silurian slates, and unconformably under the carboniferous 
rocks, hence arises the probability of the sandstone belonging to the Silurian series. 
Mr.: Griffith next directed the attention of the Section to another district of red- 
dish-brown sandstone and conglomerate, exactly similar in geolugical position, in 
composition and character, to that just described. 
This district forms a narrow mountain ridge, known by the name of the Curlew 
mountains, and extends from Drumshanbo in the county of Leitrim to the north of 
Boyle, Lough Gara, and Ballaghaderreen, to Mullaghanoe Hill near Swineford in 
the county of Mayo, forming a chain of hills thirty-two miles in length, and rarely 
more than three miles in width from north to south; the greatest elevations being 
the Curlew mountain 863, and Mullaghanoe 775 feet. 
The characteristic rock of this district is compact reddish-brown sandstone, alter- 
nating with red shale, and including tracts of metamorphic slate passing into semi- 
porphyry, precisely similar to the Tyrone district ; the conglomerates are sometimes 
trappean, but usually contain quartz pebbles in abundance. In some localities the 
metamorphic rock is schistose, and passes into compact reddish-brown slate, pre- 
senting only imperfect crystals of felspar ; in others the line of division between the 
reddish-brown sandstone and the metamorphic porphyry is quite abrupt, so as to 
give to the latter the appearance of a protruded mass. A good example of this fact 
is seen to the north of the demesne of Ballyedmond near Ballaghaderreen, where the 
metamorphic rock forms a tongue, enveloped by the ordinary reddish-brown sand- 
stone and shale unaltered, or at least very slightly affected at the contact. 
In the midst of the metamorphic porphyry in the lands of Egool, about one mile 
south of the mountain of Mullaghanoe, are found a series of rocks composed of alter- 
nations of brownish-red sandstone and shale, greenish-gray quartzite, greenish and 
bluish clay-slate, and impure gray limestone. 
The succession commencing from the north consists of a base of metamorphic 
porphyry, above which we have— 
Feet 
1. Greenish-gray quartzite, stratification irregular, about .......... 400 
2. Gray quartzose conglomerate ....... Biafelafeleiarstbiertow MARU AL 7% 150 
3. Greenish-gray fossiliferous slate .............. baeie biel seine seeees? 200 
4. Reddish-brown sandstone and shales, about...........sseeeeee 200 
5. Impure limestone, very fossiliferous........ wiv anielv aehevaviehte sicratue'e 60 
6. Darkigray slate, fossiliferous. jit). (cies <\ceincldeleeiacs + wle'evels 160 
7. Alternations of red conglomerate, red sandstone, and red sandstone 
slate nwa: deiccwinns sit webdats J Wais fae tle side meee et Bistale viewers 300 
8. Alternations of greenish-gray quartzite, sandstone and slate, about 1000 
Potalys iivews dele 2470 

