periodicity for the fresh water to form a series of convex, freshwater, Ghyben-Herzberg lenses floating on the heavier salt water in the saturated sediments...

high temperatures lead to an arid environment in which a freshwater Ghyben-Herzberg lens cannot form, and coconut palm is unable to grow. The most common...

and probably represent wedges of freshwater floating on sea water (Ghyben-Herzberg principle). The freshwater probably originated from the higher ground...