HIGHLAND BOUNDARY FAULT
The Highland Boundary Fault transverses a bit of West Dunbartonshire and knits it with Stirlingshire to the east and Argyll and Bute to the west. We see it as to emerges mysteriously from Loch Lomond and then dips again. We recognise it topgraphically as a line of islands that include Inchmurrin, Creinch, Torrinch, and Inchcailloch.
To the west it is aigned roughly southwest to northeast. It runs from Lochranza on Arran and bisects Bute before crossing the Cowal and Rosneath peninsulas. To the northeast it continues to Aberfoyle, then Callander, Comrie and Crieff. It then forms the northern boundary of Strathmore and reaches the North Sea immediately north of Stonehaven. From our vantage point at Loch Lomond we see it rise up to Conic Hill.
You can read up further about the actual dynamics of all this on the links below, but for the moment it is worth considering the enormous dramas that led to its creation.
The fault line is clearly seen in this photo taken from the sea plane. It forms a very linear arrangement in the islands (as compared to the others to the north). Conic Hill and Stirlingshire appear in the distance / east; West Dunabrtonshire to the right / south and Argyll and Bute below / west.
CATERAN ECOMUSEUM : https://cateranecomuseum.co.uk/site/the-highland-boundary-fault/#:~:text=The%20Highland%20Boundary%20Fault%20is%20a%20geological%20fault,way%2C%20it%20goes%20through%20Blairgowrie%2C%20Alyth%20and%20Kirriemuir.