HARKNESS — THE GEOLOGY OF HOOK POINT. 
29 
lifted up, the stony matter of Hook was formed, and had the arrange- 
ment which it now exhibits to us. 
Its rocks are older than the great mass of rocks which afford the 
food of the steam-engine, — man's great organ of progress, — and they 
equal in antiquity the hard grey limestones of the north of England, 
which support the coal-bcariug beds of that region. 
Hook Point is a spot of much geological interest, and the limestones 
of which, in a great measure, it consists are perfect charnel-houses of 
solid skeletons of beings which existed in an ancient sea. 
Although Hook Point is composed of strata which are known to 
the geologist under the name of the Carboniferous Limestone, these 
are not the only rocks which enter into the composition of the 
promontory terminating in this headland. The whole of the geology 
in connexion with this portion of the county of Wexford is of great 
interest, and tells of circumstances and agencies which produced 
different results, as these several conditions and agencies differed from 
each other. The structure of the great mass of the county of Wexford 
consists of rocky strata, which are designated Lower Silurian, and which 
are equivalent, in geological age, with the great mass of rocks forming 
the mountainous range traversing Scotland from north-north-east to 
south-south-west, south of the Forth and Clyde, and which is now known 
under the general name of the Southern Highlands of Scotland. Wales, 
too, has rocks which occupy the same geological position ; and from the 
circumstance that these rocks are well developed in the neighbourhood 
of the town of Llandeilo, the illustrious author of the Silurian System 
has given them the name of Llandeilo-flags. In the south of Ireland 
these Lower Sihu'ian rocks consist not only of deposits such as emanate 
from the ordinary action of marine causes, but they have, associated 
with the usual products of aqueous action, beds of ashes resulting 
from the matter evolved from ancient volcanos, which were in active 
operation at that remote geological epoch ; and these volcanic ashes, 
falling upon the surface of the ancient sea, were sifted and arranged, 
and finally deposited among shells and corals, imbedding these animal 
remains often in particles which retain, to a great extent, their original 
crystalline form, as the ash of felspathic lava. None of these ancient 
ashes enter into the structure of the promontory of which Hook Point 
forms the sovithern termination, although they approach very nearly 
