Stromatolites of the Lesser Himalayan Carbonate Formations and the Vindhyans

A number of carbonate formations of the Lesser Himalaya and the Vindhyachal have been found to display widespread and prolific development of stromatolites. These are confined to definite stratigraphic horizons and exhibit no influence of facies changes. Time-controlled changes are clearly expressed in their morphology and the 'regular sequence of different forms over extensive areas suggests their evolutionary variation.

The Fawn Limestone of the Semri Series of Southern Mirzapur exhibits bioherms of Conophyton cylindricus and Collenia columnaris with C. kusiensis, characteristic forms of the Lower Riphean formations (older than 1260 m.y.) of U. S. S. R. The Bhander Limestone of the Upper Vindhyan, the Gangolihat Dolomites of the Calc Zone of Pithoragarh, the Lower Deoban Limestone of Dehra Dun District, the Lower Shali Limestone of Mahasu District and the Tundapatthar Limestone of Ambala District are characterized by Collenia baicalica, with C. cotumnaris, C. symmetrica and C. buriatica. These forms constitute typical Middle Riphean (1260 to 1000 m.y.) stromatolite-complex of U. S. S. R. The Thalkedar Limestones of Pithoragarh, the Upper Deobans and the Upper Shali Limestone contain what look like Jurusania of the Upper Riphean formations of the southern Urals in U. S. S. R. Kakarhatti and Naldera stromatolites seem to be of a still younger age.