Dr John Grant Malcolmson and a reconciliation of the Middle Devonian Lethen Bar and Lethen House fish bearing nodule localities

Abstract

The area known as Lethen Bar and Clune, SE of Nairn, Scotland, is a classic Middle Devonian locality which has yielded nodules or concretions, some of which contain fossil fishes with the highest quality of preservation. The locality was largely centred on farm limestone quarries situated around the perimeter of an isolated outlier of the main fishbed. It was first described in the 19 th century, although the upsurge in collecting fossil fishes only occurred some twelve years after the quarries were first mentioned in the scientific literature. Our knowledge of the provenance of the locality is based on very limited accounts, which have never been scientifically tested; these accounts also contain apparent anomalies that have never been adequately addressed. Based on these anomalies, the author of a paper published in 1983 proposed that the locality had been untraceable since the late 19 th century and that the outcrop was quarried out. In 2005, the present authors recorded the first scientifically detailed stratigraphical section of the fishbed, followed in 2021-2023 by detailed field surveys and by a re-appraisal of the literature. This work has resolved the 19 th century anomalies and enabled us to confirm the locations of old quarries, to give affirmation to two previously unrecognised sites, and to show that the outcrop is still present. Thematic collection: This article is part of the Geology of Scotland collection available at: https://www.lyellcollection.org/topic/collections/geology-of-scotland