The geology of Loch Lomond and The Trossachs National Park in the southwestern part of the Scottish Highlands consists largely of Neoproterozoic (late Precambrian) and Palaeozoic bedrock faulted and folded and subjected to low grade metamorphism during the Caledonian orogeny.
A part of this mountainous park extends south of this major geological divide into an area characterised by younger Devonian rocks which are assigned to the Old Red Sandstone.
The Inverclyde Group is present in a couple of outliers immediately north of the Highland Boundary Fault to the east and west of Loch Lomond.
The eastern outlier forms the ground just to the north of Conic Hill and is assigned to the Kinnesswood Formation which consists of sandstones, often conglomeratic at their base, together with mudstones and cornstones (nodular carbonates).
[3] The Ballagan Formation which includes mudstones and siltstones within which are thin beds (or sometimes just nodules) of ferroan dolomite, traditionally referred to as ‘cementstones’, is represented by a very small inlier on the park's southwestern boundary.
Mineral-rich fluids percolated through the Dalradian rocks in the Tyndrum and Cononish areas depositing lead, iron and copper sulphides in mineral veins.
After the end of the last ice age, there was a brief return to full glacial conditions between 12,700 and 11,500 years ago; a phase known throughout Britain as the Loch Lomond Stadial.