The Central Lowlands, sometimes called the Midland Valley or Central Valley, is a geologically defined area of relatively low-lying land in southern Scotland. It consists of a rift valley between the Highland Boundary Fault to the north and the Southern Uplands Fault to the south. The Central Lowlands are one of the three main geographical sub-divisions of Scotland, the other two being the Highlands and Islands which lie to the north, northwest and the Southern Uplands, which lie south of the associated second fault line. It is the most populated of Scotland’s three geographical regions.
Arthur's Seat in Edinburgh
The Highland Boundary Fault is a major fault zone that traverses Scotland from Arran and Helensburgh on the west coast to Stonehaven in the east. It separates two different geological terranes which give rise to two distinct physiographic terrains: the Highlands and the Lowlands, and in most places it is recognisable as a change in topography. Where rivers cross the fault, they often pass through gorges, and the associated waterfalls can be a barrier to salmon migration.
View along the Highland Boundary Fault from Conic Hill – the topographic ridge is mainly due to the presence of Devonian age conglomerates on the southwestern side of the fault and can be traced across Loch Lomond on the islands of Inchcailloch, Torrinch, Creinch and Inchmurrin, to Ben Bowie on the western shore
Altered serpentinite and associated sediments of the Highland Border Complex caught up in the fault zone – exposed on Druim nam Buraich, near Balmaha
Lower Devonian sandstones and conglomerates of the Inchmurrin Member dipping steeply to the southeast close to the Highland Boundary Fault trace near Balmaha