Oryctocephalus salteri biozone (Wuliuan, Miaolingian) in the Sumna Valley, Spiti, Himalaya

Abstract

We precisely demarcate the Oryctocephalus salteri biozone in the Cambrian Parahio Member (Kunzam La Formation) well exposed on the southwest-facing slope above the right bank of the Sumna River, Spiti. The FAD and LAD of O. salteri are located at 46.5 m and 60.8 m respectively, indicating a 14.3 m local stratigraphic range of the taxon along the section in Sumna Valley, Spiti. The O. salteri biozone is demarcated with a precise stratigraphic range of the eponymous species. This biozone contains trilobites O. salteri, Kunmingaspis stracheyi, Poriagraulos sp., Ziboaspis hostilis, Hundwarella memor, and Xingrenaspis hoboi. Based on the presence of the key taxon Hundwarella, the O. salteri biozone of the Kunzam La Formation (Spiti) is correlated with the Tonkinella-Hundwarella bearing level in the Nutunus Formation, Kashmir region.