A Revision of the Fauna of the North WelshConocoryphe violaBeds implying a Lower Cambrian Age

Abstract

Fossils collected during the past sixty years from the uppermost division of the approximately 2,000 ft. thick Llanberis Slates have been re-examined. All but one fossil came from the famous Penrhyn Quarries at Bethesda, Caernarvonshire. The fauna is described as containingPseudatops viola(H. Woodward),Eodiscus sp., cf. Protolenus howleyi(Walcott),Hyolithes cf. hathewayiG. F. Matthew,H. sp., and a fragmentary crustacean. The last offers no evidence of age but the remainder are considered to indicate a high Lower Cambrian horizon. Illustrations of some of these fossils are given for the first time. TheHyolithesis interpreted as carrying a pair of fin-like skeletal outgrowths and the morphological significance of these is discussed in a statement which comments on the obscure systematic position of the Hyolithidae.