Geological Relations of the East of Ireland . 281 
to be observed ; but from the lowness of the coast on this side, the 
sandstone conglomerate is often concealed h>y the shifting of the 
gravel on the beach. 
The clay slate, on the north side of the sandstone conglomerate, 
forms a bed about five fathoms in width, containing numerous veins 
and strings of calcareous spar. This conglomerate constitutes a 
body about fifteen fathoms in thickness, subdivided into strata front 
one to four and a half feet thick. Excellent millstone might be 
•raised here, were not the situation so much exposed to the assaults 
of the sea. The two kinds of rock are sensibly affected by their 
•proximity to each other ; the conglomerate appearing in the form 
of a more or less coherent gravel and sand, of a deep red colour, for 
five or six yards in width, and the clay slate, where in contact with 
it being decomposed for about the same extent. The greenstone 
on the south side of the sandstone conglomerate is similarly affected, 
and worn away, but the strata of conglomerate stand firm, and form 
-a small promontory, projecting eastward into the sea. On the 
north side these strata are laid bare by the sea for about 200 yards 
in length, being fifty feet high in the highest point, and presenting 
an inclined face in that direction. 
This sandstone conglomerate consists of pebbles and angular frag- 
ments of i eddish brown iron shot quartz and white quartz, with 
smaller similar particles, agglutinated by a siliceous cement and a 
minute portion of reddish brown iron-shot sandy clay, constituting a 
hard, firm, and coherent rock. The reddish brown quartz some- 
times approaches to the nature of iron flint. In the rock itself may 
•also sometimes be observed disseminated portions of lamellar heavy 
spar. 
, From the preceding description, it is evident that a considerable 
degree of analogy subsists between the transition rocks *>f Lambay 
