Geological Relations of the East of Ireland. 271 
pears to be intermingled with calcareous matter. The organic re~ 
mains are principally bivalves, anomites, pectunculites, and terebra- 
tulites, with entrochites in smaller number. In the more solid 
stone we sometimes find the shells themselves ; but nearer to the 
surface they have in most cases wholly disappeared, leaving only 
distinct and delicately marked impressions of the surfaces of the 
valves, the space between them being occupied by greenstone. In 
the same manner, casts of the entrochite occur, in the form of 
hollow and solid cylinders. These organic remains seem to be< 
confined to that portion of the rock, which is in the vicinity of 
the limestone ; for none are to be discerned in the remaining mass 
of the hill, which exhibits every where rocky protuberances from 
one continuous body of greenstone and porphyry. The only other 
rock visible is clay slate, standing in strata nearly vertical, which 
appears low down on the western side and at the base of the hill, in 
that quarter; (§137.) 
§ 171. But, it is in the county of Limerick that the interstrati-^ 
fication of the floetz limestone with trap rocks becomes distinct and 
well marked, both on the large and on the small scale : and if we 
examine the calcareous tract from the Bilboa mountains on the 
north, for some distance south of the parallel of Pallis and Caher- 
eonlish, we may trace these relations in succession. 
§ 172. On the north side of the valley, I have already noticed 
(§ 139.) the outcrop of the floetz limestone at Castleguard, where 
it probably lies upon the sandstone of the Bilboa mountains, the 
dip being conformable. If we now take post on the northern brow 
of Pallis hill, which is elevated about 500 feet above its immediate 
base, and overlook the country, we perceive the surface of the vale 
below diversified by unequal, indented ridges of slight elevation, 
which cross the valley under an oblique angle, in a nearly parallel 
