A Note on a Fossiliferous Shale in Coastal Sedimentaries, North of Madras

This paper highlights the geomorphic and palynological significance of the carbonaceous shale horizon subcropping 3 m below surface in the pits dug in the Korttalaiyar river section near Kondakarai, north of Madras. The carbonaceous shale underlies recent alluvial sand and appears to overlie Cuddalore Sandstones which are exposed to the west.

The palynological assemblage recovered consists of fungal spores, pteridophytic spores and angiospermic pollen grains. The pteridophytic spores are referable to Polypodiaceae, Cyatheaceae, Dicksoniaceae and Parkeriaceae, of which the Polypodiaceae represents the predominant taxon. The angiospermic pollen grains are referable to monocotyledonous and dicotyledonous taxa. The pollen grains of the following families have been recognised., viz., Palmae, Rhizophoraceae, Verbenaceae, Chenopodiaceae, Lecythidaceae, Caryophyllaceae and Leguminosae. Of these, the pollen grains of Rhizophoraceae and Verbenaceae are the most abundant. The spore and pollen assemblage indicates a Neogene-Quaternary age and points towards the presence of brackish water mangrove vegetation.