Geological Relations of the East of Ireland. 23*7 
Knockbuye, to the south of Long Leg. It was here formerly 
quarried, but a few square perches only are now visible, being 
elevated two or three feet above the surface of the sea at ebb tide. 
To the north, the transition rocks appear to follow the coast to the 
mouth of the Boyne, and still farther north they probably abut upon 
the clay slate and greywacke hills of Louth, Meath, and Cavan; in 
which quarter, we may perceive three basins of floetz limestone re- 
posing on the slaty rocks, one in the vicinity of Drogheda, another in 
that of Ardee, and a third, of greater extent, surrounding Carrick- 
macross. 
§ 132. Louglishinny copper mine appears to have been con- 
ducted in transition rocks of narrow extent, denuded of the floetz 
limestone on the northern and eastern sides, but surrounded and 
covered by the latter formation in every other quarter. In the old 
hillocks we may observe fine grained greywacke, clay slate, and 
greywacke slate, and some fine granular greenstone ; these rocks 
appearing there to bear a close analogy to those which occur on the 
coast south of Balbriggan. The ore was of a rich quality, but 
apparently derived from contemporaneous veins of quartz of un- 
certain extent. In the bank on the coast below, clay slate appears 
supporting the floetz limestone formation, but it is sometimes con- 
cealed by the shifting of the shingle on the beach. 
III. j Floetz Tracts. 
§ 133. These comprehend old or first floetz sandstone, the 
floetz limestone formation, and the coal districts. 
1. First Floetz Sandstone . 
§. 134. This rock, within the tracts now under consideration, 
is found resting upon granite, upon clay slate, greywacke, and 
