Late Middle Cambrian trace fossils from the Lejopyge armata Horizon, Zanskar Valley, India and the use of Precambrian/Cambrian ichnostratigraphy in the Indian subcontinent

Trace fossils from loose slabs of shale containing latest Middle Cambrian trilobites from the Zanskar Valley show a variety of morphologies indicating surficial and shallow infaunal activity. The absence of definitive arthropod trace fossils in rocks which contain trilobites emphasises that not all Indian trace fossil assemblages that postdate the appearance of arthropods contain trace fossils made by these animals. This questions the validity of recently proposed ichnostratigraphical schemes for the Himalayan Cambrian which rely on arthropod traces to date the enclosing sedimentary rocks. A list of papers concerning putative early trace fossils from Proterozoic deposits on the Indian shield documents an extensive published literature on this matter.