• Sea level rose again as deposition of the Harudi Formation began. It initiates with a paralic setup and deepens towards the top, thus representing a transgressive systems tract (Banerjee et al., 2012). Grey shale along with the presence of streaks of lignite, limonite pseudomorph after pyrite etc. in the lower part indicates a low-energy reducing condition of a lagoon to littoral environment of deposition (Biswas, 1992; Mukhopadhyay and Shome, 1996a,b). The basal gray shale indicates deposition in a shallow, quiet lagoon, witnessing occasional exposures. The shelly limestone facies with sharp lower contacts, gradational upper contacts and intraclast concentration at base suggests high-energy deposits (Kidwell, 1991; Kumar et al., 2009). Minor fragmentation of shells, low faunal diversity and chaotic arrangement of shells corroborates event deposition. In alternation with grey shale, this facies with its general matrix-rich nature appears to be storm wash-over carbonate sand in the lagoon.

• The Middle Eocene Harudi Formation is also argillaceous. Bands of carbonate concretions and thin mollusc shell beds alternate with grey shales in the lower part of the formation. Cimomia forbesi comes from the shell beds and concretions lying below the nummulitic limestone.