Portnellan - Ross Priory - Claddochside
Condition (NatureScot)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| F1 | Quaternary of Scotland | Favourable | — | 2009-10-29 |
Climate exposure
This is about exposure to a nationwide pressure this habitat type carries — not a verdict on this site's own management.
Coastal habitats are exposed to sea-level rise and storm erosion. Where hard sea defences sit behind them, there's nowhere landward to retreat to — a squeeze that keeps compressing the habitat no matter how well it's managed.
Geology & landscape
Landscape processes: Coastal, Glacial
Description
Portnellan - Ross Priory - Claddochside Portnellan - Ross Priory - Claddochside Site of Special Scientific Interest (SSSI) is a composite site in three parts located on the southern shore of Loch Lomond about 5 km north of Balloch and 2 km north-west of Gartocharn. This site is the best example in the West Dunbartonshire Council area of the late glacial and post glacial processes of the Loch Lomond Readvance. Together, these three compartments provide important stratigraphic and geomorphological evidence for the Late glacial sequence of marine and glacial events in the type area for the Loch Lomond Advance. They demonstrate a Late glacial marine transgression, indicated by “Clyde Beds” at Claddochside, followed by the formation of a very prominent shoreline seen as an impressive rock platform at Ross Priory. This shoreline has been correlated with the Main Late glacial shoreline of western Scotland. At Portnellan the platform and backing cliff are covered by Loch Lomond Advance till, providing clear evidence that the shoreline was formed before the glacier advance reached its maximum extent. The till also buries the “Clyde Beds” at Claddochside. A further marine transgression after the Loch Lomond Advance is indicated by the Main Postglacial Shoreline represented at Portnellan and Ross Priory, whose width in part reflects exhumation of the Main Late glacial Shoreline. The three compartments thus provide a key assemblage of geomorphological and stratigraphic evidence demonstrating that the Loch Lomond Advance in its type area represents a distinct glacier advance after a period of marine transgression, sedimentation and shoreline formation. Furthermore, they illustrate the detailed pattern of Late glacial and Postglacial changes in relative sea level.