Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/159



The conglomerate contains in great abundance large pebbles of quartz, and more rarely of hornstone porphyry; also of a rock which appears to have been a greenstone porphyry, but is much altered by decay; and lastly of mica slate. The coarsely granular variety consists of quartzose concretions imbedded in an argillo-calcareous cement.

This sandstone formation appears to rest on the mica slate which succeeds it on the north side of Cushendon bay, and occupies the district of Cushleak described in a former article. At the opposite or N.W. extremity of that district we may again trace the sandstone in Murloch bay: it there appears very distinctly on the beach near the great Whin dyke, in its conglomerate form.

To the westward of Church bay in the Isle of Rathlin, and near a spot called the Black rock, I found fragments of the old sandstone associated with blocks of syenite in such abundance as to impress me with a strong belief of the former existence of both these rocks