Westerdale Quarry

Also within

Caithness County

Condition (NatureScot)

Geology & landscape

Mining / Industrial: Quarry · Geological Period: Devonian · Rock Type: Siltstone

Description

Westerdale Quarry Westerdale Quarry SSSI is a small quarry 1km west of the village of Westerdale and 18km south of Thurso, Caithness. The site has been notified due to the exposure of a 1m-thick bed of laminated, calcareous, grey siltstone that is rich in well-preserved fossil fish. The fossil fish bed has been exposed here as a result of quarrying to extract flagstones. The fish bed at Westerdale dates from the Middle Devonian geological time period, approximately 380 million years ago, when the area now known as Caithness was a large inland lake. This quarry forms part of a network of sites across northern Scotland where Middle Devonian fossil fish beds have been exposed. The fossil bed exposure at Westerdale is significant as it is the oldest in the sequence. The quarry contains specimens of Thurius macrolepidotus and Dipterus valenciennesi, two species of early bony fish present at the beginning of a major phase in fish evolution during the Middle to Late Devonian. Fossils of these species are exceptionally well preserved at Westerdale and complete specimens are common. This site is of national importance in the study of early vertebrate evolution.