Thornylee Quarry
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Condition (NatureScot)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| F1 | Llandovery | Favourable | — | 2008-09-18 |
Geology & landscape
Mining / Industrial: Quarry · Geological Period: Silurian · Rock Type: Shale
Description
Thornylee Quarry Thornylee Quarry is located immediately to the north of the A72, 7.5 kilometres east of Innerleithen, and includes part of the disused railway line from Peebles to Galashiels. This site is of national importance for its exposures of sedimentary rocks produced 430 million years ago by sediment deposited during the Llandovery Epoch within the lower Silurian geological time period, now tilted to lie at a near vertical orientation. The interbedded mudstones and greywackes of the late Llandovery Gala (Queensbury) Group were formed as a result of sediments deposited in deep water. The sedimentary sequence contains a greater proportion of fine grained sediment compared with other localities of the same age in the Southern Uplands and is famous for its abundant and diverse trace fossil assemblage. Trace fossils are structures in the sediment produced by the activity of ancient organisms, such as traces of the movement of ancient worm-like organisms scavenging for food in the soft muddy sediment seen on some of the shale surfaces at Thornylee.