Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/169



1. The valley of the river Lagan from Moira to Belfast, and the north-west shore of Belfast Lough as far as the Peninsula of Magee.

2. Several points on the north-east coast of Antrim.

3. A line in the eastern division of Derry and north east of

Tyrone, extending from the mouth of the river Roe to the south west extremity of Lough Neagh.

1. Sandstone of the valley of the Lagan and Belfast Lough.

The sandstone formation may be traced from the south west extremity of the county of Antrim, where it joins that of Down, occurring between Moira and Lisburn, at Maherameslt, Spencer's bridge and Maheragall; it proceeds along the valley of the Lagan, extending into that of the Forth, a small river which becomes tributary to the Lagan near Belfast; from that town it occupies the road to Carrickfergus, whence it ascends the valley of the Woodburn, another brook discharging itself into Belfast Lough; it afterwards extends as far as Castle Chichester, in the island of Magee.

The prevailing colours of this sandstone are various shades of red and reddish brown, but it is variegated by many coloured stripes; it contains clay-galls; its texture is friable; the cement is calcareous; spangles of mica constantly occur.

At Carrickfergus, where the rock is more than usually adherent, it is raised for flags.

The upper members of this formation become argillaceous, consisting of beds of reddish brown marle, alternating with a greenish slaty marle, and an indurated grey calcareous marle; these may be