Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

A. V. Vartak ¹, M. A. Ghare ¹

Affiliations
1 Department of Geology and Palaeontology, M.A.C.S. Research Institute, Pune 411004, IN

Abstract

Paper reports the presence of the genus Worthoceras Adkins from the Utatur Group, Cretaceous deposits of Tiruchchirapalli, Tamil Nadu. The genus is represented by three species, viz., Worthoceras vermiculian, W. gibbosum and Worthoceras sp. aff. W. rochatianum. History and phylogenetic position of the genus is discussed in detail. Authors following Henderson (1973), place the Wortoceros species under the family Scaphitidae and consider the genus Otoscaphites Wright as an evolutionary form in the lineage Eoscaphites-Scophites.

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R. M. Badve ¹, C. V. Sakurkar ², A. V. Vartak ³

Affiliations
1 425/75, T. M. V. Colony, Pune - 41 1 037, IN
2 47/4, Samir Apts. Taware Colony, Pune - 411 009, IN
3 Department of Geology, N. Wadia College, Pune - 41 1 001, IN

Abstract

Occurrence of fossiliferous clay beds underlying the laterite cap and containing palynofossils has been recorded from Goa State. The first occurrence is from the north bank of Mandovi river at the bridge on Mapusa-Panaji road where bluish grey clay yielded spores. The second occurrence is from the Iron Ore Mine of M/S Lithoferro Pvt. Ltd. at Village Sangod, South Goa. It exposes carbonaceous clay containing carbonized plant debris. Palynoassemblage, comprising elements such as Ceiba sp., Cocos nucifera, palm sp., Lycopodium inundata, Lygodium fiexuosum, Ceratopteris thalictroides, Ceratopteris sp. etc., along with microforaminiferal organic linings indicates estuarine environment of deposition and the climate to be tropical and humid with high rainfall. Further, presence of marcasite in these clays associated with strong sulphurous odour also points out their deposition under reducing condition. On the basis of the mode of occurrence and palynoassemblage, these clays correspond to the Ratnagiri Beds exposed in Ratnagiri and Sindhudurg Districts of Maharashtra State, suggesting that the clay beds of Goa are the southward extension of Ratnagiri Beds. Neotectonic activity is reflected by the uplift of estuarine sediments above the prcsent sea level as well as the deeply entrenched and highly meandering river courses in the study area.

Keywords

Fossiliferous Clays, Palynology, Estuarine Conditions, Neotectonic Activity, Goa.

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