30 
THE GEOLOGIST. 
thereto. The mass of rocky strata which more properly appertains 
to Hook has an age much more recent, and the older rocks have 
undergone not only consolidation, but have been subjected to the 
action of violent subterranean forces, which have bent, twisted, and 
elevated the older masses, long previous to the period when the 
conditions prevailed which gave rise to these newer rocks which make 
up the headland of Hook. Those more ancient rocks have to a con- 
siderable extent furnished the materials out of which a portion of the 
Hook promontory was constructed, and they affoi'd evidence that, 
after the twistings and elevations referred to, a portion of their area 
formed the margins of the sea from whence resulted the rocky masses 
which more immediately support the Carboniferous limestones of Hook 
Point. The western side of Hook, at a small bay near the village of 
Templetown, among the rocks of the coast, gives us an insight into 
the physical causes which were the prelude to those conditions from 
which the limestones, rich iu organic remains, emanated. Here we 
find coarse sandstones, and sometimes there are what are known to 
geologists under the name of conglomerates, consisting of rounded 
pebbles cemented together by a sandstone-base, and recording in their 
structure the fact of their having been originally fragments broken 
by the action of ancient waves from previously existing rocky coasts, 
and afterwards ground upon each other, each one rubbing from its 
neighbour its angularity and asperities in the same manner that we 
find, at the present time, the sea-margins of even rocky coast fringed 
by an outline of pebbly beach, the result of the force and abrading 
power of the ever-restless ocean. 
. These conditions of an agitated sea, preceding the formation of the 
newer and overlying rocks, were succeeded by features of a more 
tranquil nature, with respect to the ancient physical geography of 
this portion of Ireland. The sandstones became gradually less coarse ; 
and in the strata which are intermediate between the conglomerates 
below and the limestones above, traces of organic beings begin to make 
their appearance. These consist of fragments of land-plants, having 
a coaly aspect, and, on the whole, indistinct as to their characters. 
They bear about them sufficient evidence to show that they formerly 
flourished on the surfixce of the earth as the stems of ferns ; and 
from their nature and geological position, there is strong reason for 
