Occurrence of Kockelella variabilis Walliserin the Aymestry Limestone of Shropshire

Abstract

A COLLECTION of 1,400 conodonts collected by one of us (G. N.) in the course of a regional study of the Upper Silurian of Shropshire was submitted to the other (F. H. T. R.) for identification. Among these were found twelve fragmentary specimens not included in the fauna described by Rhodes¹ from the Aymestry Limestone. These represent Kockelella variabilis Walliser, originally recorded from the Silurian of Germany (from the Rheinisches Schiefergebirge, basal Orthocerenkalkes of Frankenwald and the Cardiola Horizon of the Karnische Alps²). The genus has also been reported from the Province of Malaga in Spain³, the Lower Ludlovian of the Regganne area of southern Algeria⁴ and the Silurian of the Tindorf Basin of the Spanish Sahara⁵. Ziegler⁶ considered the species a good index for rocks of Middle Ludlovian age, but Walliser⁷ showed it as characteristic of the Lower Ludlow. It therefore seems useful to record and illustrate the occurrence of the present specimens, which suggest an extension of the known range of the genus, even though the specimens are too fragmentary to provide any new morphological information.