A scientific study of the palynological characteristics of the lagoon was conducted by taking sedimentary soil samples from four test pits. It shows that the vegetational reconstruction from peat beds at a.m.s.l. and (a.m.s.l.) in the west at Sullurpeta and Kasdredinilem, respectively, is indicative of a palaeoshoreline. The sea level reached its maximum around 6650 plus or minus 110 yrs BP in Sullurpeta, west from the present shoreline. The radiocarbon dates of peat bed at Kasdreddinilem reveals an age of 4608 plus or minus 122 yrs BP, indicating the shift in mangrove line eastwards during the regressive phase.