Trace fossils from the Pin section of Spiti Valley, Himachal Pradesh and their stratigraphic significance

The Early Cambrian trace fossils Planolites, Skolithos, Psammichnites, Neonereites, Didymaulichnus, Monomorphichnus, Dimorphichnus, Diplichnites, Rusophycus and Cruziana are described from the Kunzum La Formation (Haimanta Group) of the Pin section in Spiti valley. These trace fossils occur well below the body fossil zone reflecting their abundance at two stratigraphic levels. The Precambrian-Cambrian boundary could be well below the earliest trace fossil horizon. The abundance of trace fossils at these two levels is a universal phenomenon in the Himalaya and indicates two acme zones with proliferation of vermiform organisms in the lower zone and arthropod forms in the upper zone.