Ichnogenus Palaeophycus Hall from the Bagalkot Group, Karnataka State

Horizontally disposed, curved to gently sinuous, unbranched burrows, with a thin but distinct lining, are found at village Mardi Shivapur, Belgaum district, Karnataka State. They occur In the Yadha lll Formation, Lokapur Subgroup, Bagalkot Group, Kaladgi Supergroup. On the basis of presence of thin wall and fairly uniform diameter, these burrows are identified as Palaeophycus tubularis, Hall. Draping of later burrows over earlier ones and downward deflection of sediment laminae due to bioturbation provide evidences for their biogenic origin. In view of the radiometric dates of the Kaladgl rocks, these burrows are assigned a mid-Riphean age. This not only sets the lower limit ofthe range ofthe ichnogenus Palaeophycus at mid-Riphean, but also supports the view of Glaessner that the metazoans appeard some 1000 m.y. ago, much earlier than the Ediacaran period.