of the North of Ireland, 161 



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 ex- 

 tremity of the county of Antrim, where it joins that of Down, 

 occurring between Moira and Lisburn, at Maheramesk, Spencer's 

 bridge and Maheragall ; it proceeds along the valley of the Lagan, 

 extending into that of the Forth, a small river which becomes tribu- 

 tary to the Lagan near Belfast ; from that town it occupies the 

 road to Carrickfergus, whence it ascends the valley of the Wood- 

 burn, 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, con- 

 sisting of beds of reddish brown marie, alternating with a greenish 

 slaty marie, and an indurated grey calcareous marie ; these may be 



* On the opposite side of Belfast Lough this sandstone extends towards Holwood, 

 where it rests upon the limestone before described, and we traced it for some distance on 

 the road from Belfast to Newton onwards. 



Vol. III. X 



