253 
Geological Relations of the East of Ireland . 
ing the form of the surface of this rock. Conglomerate also occurs 
in this quarter. The clay slate to the east of Slievenaman, extend- 
ing toward Kilmagany, yields very good slate, as for example in 
the quarries of Tnshinagloch. 
§ 151. At Thomastown the sandstone crosses the Nore ; and 
from thence follows the foot of the clay slate hills until it comes in 
contact with the fundamental granite to the north-west of Graige, 
in strata dipping 20° toward the north-west, and forming the 
western and north-western sides of Mount Loftus and Brookhill. 
After crossing the Barrow, it re-appears for a short distance to the 
north-east of Goresbridge, dipping 15® to the north-west, and repos- 
ing on the granite. The sandstone at these places has much the 
aspect of a rock compounded of the detritus of granite, in which,, 
however, quartz greatly predominates. 
§ 152. In the interior of the great limestone plain, we may 
remark three isolated protuberant masses of sandstone, rising from 
beneath the limestone, as at Moat, Ballymahon, and in Slieve- 
goldryhill. And to the west of the clay slate country in the county 
of Longford, this rock may be observed occupying a more con- 
siderable space, crossing the Shannon, and extending into the 
counties of Roscommon and Leitrim. 
§ 153. Three general observations are applicable to the sand- 
stone tracts over which we have travelled : 1st, That the position 
of this rock, when in contact with older rocks, is dependent upon 
the declivity and form of the subjacent surface ; but that as the 
sandstone strata accumulate and recede from the rock beneath, they 
tend more and more toward an horizontal arrangement. 2nd, That 
not the slightest vestige of organic remains has appeared in this 
first floetz sandstone, in the course of the observations of which 
I have given the result. 3rd, That this rock has not been any 
where seen by myself interstratified with any other rock ; except 
