i io Old Red Sandstone. 



In North Wales narrow streaks of Old Red Sand- 

 stone here and there crop out between the Upper 

 Silurian rocks, and the Carboniferous Limestone of 

 Flintshire and Denbighshire, and the same with bands 

 of corn stone forms the fine escarpment of Traeth 

 Dulas in Anglesey, where the sandstone lies directly on 

 Lower Silurian rocks. 



In the northern counties also, at Kirkby Lonsdale, 

 Sedbergh, and Kendal, and all along the base of the 

 Carboniferous Limestone between Orton in Westmore- 

 land, and Greystock Park in Cumberland, patches and 

 a long line of Old Eed Sandstones, marls, and con- 

 glomerates occur. 



A broad belt of Old Red Sandstone crosses Scotland 

 in a north-east direction between the Firth of Clyde 

 and the Firths of Forth and Tay, and Stonehaven in 

 Kincardineshire, and Montrose. Patches lie in Arran, 

 Bute, &c. The whole lies unconformably on Lower 

 Silurian clay slates, and dips to the south-east under 

 the Carboniferous rocks that occupy the great central 

 depression through which the Forth and Clyde chiefly 

 run. On the south-east side of this broad undulating 

 hollow the Old Red Sandstone again rises from beneath 

 the Coal-measures with a general north-west dip, and 

 skirting the Lammermuir Hills, strikes south-west into 

 the sea south of Ayr. On the south side of the Lam- 

 mermuir Hills, it again appears on the hills between 

 St. Abb's Head and Hawick, dipping under the Car- 

 boniferous rocks that, without a break, stretch from 

 Berwick to the neighbourhood of Derby. 



North of Stonehaven detached patches of Old Red 

 Sandstone occur on the mainland as far as Pentland 

 Firth, beyond which it forms the greater part of the 

 Orkneys, and small portions of the Shetland Islands. 



