Birkenhead Burn

Also within

Lanarkshire County

Condition (NatureScot)

Geology & landscape

Geological Period: Silurian

Description

BIRKENHEAD BURN Birkenhead Burn, approximately 5.5 km south west of Lesmahagow, is one of a network of Silurian sites in the Midland Valley of Scotland that yields important vertebrate fossil-bearing rocks. Several fossil-bearing rock exposures, on the south side of the Birkenhead Burn, are of the Slot Burn Formation of the Waterhead Group. These rock exposures are probably of Wenlock age, which formed approximately 430 million years ago. The fossilised agnathan (jawless fish) assemblage is typical of the upper fish beds from the Midland Valley Silurian inliers. These units have been correlated with similar units at Slot Burn, the historic source of the agnathans. The assemblage consists of the fossil fish, Ateleaspis tessellata (the oldest known cephelaspid), the anaspids Birkenia and Lasanius, and the thelodonts Logania and Lanarkia. These primitive jawless vertebrates are all rare and important because of the information they can supply about the early origins of vertebrates, the first developments of bony exoskeletons, and the life-styles of the first primitive ‘fish’. The site is consequently of both national and international importance for its role in providing important information on the origin and evolution of vertebrates.