No | Zone | Nature | Bedrock depth | Composition |
---|---|---|---|---|
1 | North | Coastal alluvium followed by Gondwana clay | 28–90 | Recent alluvium Sand-silt, Shale, Sedimentary rocks |
2 | South | Crystalline rocks with top soil cover | 25 | Silt–clay, Charnockites, Weathered rocks |
3 | West | Alluvium followed by Gondwana clay, Shales, Crystalline rocks | 24–90 | Mixed alluvium Clay Shales, Sand stones |
4 | Central | River alluvium followed by Crystalline rock | 30 | Alluvium Silt–clay, Gondwana shales |
5 | East | Coastal alluvium followed by Crystalline rock | 5–30 | Sand / Silt, Sand dunes, Marine fluvial clay Crystalline rocks |