Uppermost Telychian graptolites from the North Esk Inlier, Pentland Hills, near Edinburgh

Abstract

Synopsis The North Esk Inlier is an important outcrop of Silurian strata, well known for the abundance, quality and variety of fossiliferous material present. It records a significant segment of the sedimentary and tectonic history of the Midland Valley of Scotland. Numerous graptoloid specimens have recently been discovered and identified, and this has enabled the graptolite biostratigraphy of these deposits to be determined more accurately. The marine sediments of the North Esk Group have for many years been referred to as Upper Llandovery (Telychian), Monoclimacis crenulata Biozone age. The species now known to be present, are better and more precisely accommodated within the biozonal scheme of Bohemia, which is considered to be a refinement of the existing ‘British’ scheme, and correlation of relevant graptolite biostratigraphical schemes is considered. The sediments of the North Esk group are shown to range in age from the middle of the upper Llandovery spiralis graptolite interval, to lowest Wenlock. The graptolite species present are illustrated.