Carboniferous rocks within this region occupy a broadly east–west graben, referred to
as the Northumberland Trough within Northumberland (Bewcastle to the North Sea
coast) and the Solway Basin in the vicinity of the Solway Firth, where much of the
succession is obscured by Permo-Triassic strata (Fig. 13.1). The graben is bounded to
the south by the Maryport-Stublick-Ninety Fathom Fault System, which forms the
northern boundary of the Lake District and Alston blocks (see Chapter 12). The
Carboniferous rocks are broadly separated from the Midland Valley of Scotland
(Chapter 14), to the north, by the Lower Palaeozoic rocks of the Southern Uplands,
which formed an emergent upland area throughout much of the Carboniferous, with
local deposition within small basins. At the eastern onshore extent of the Southern
Uplands a relatively condensed Carboniferous succession was deposited upon the
Cheviot Block
