Pleistocene marine limestones are relatively rare on Bermuda and they can be difficult to identify. Where Pleistocene marine deposits are preserved on land, their height is generally above that of equivalent modern sediments; so they provide very good evidence of high sea level events during the Pleistocene epoch. The significance of these high sea levels is the reason that such emphasis is placed on the identification and interpretation of marine limestones.
The nature of modern marine sediments at Bermuda is important
to the Geology, because they duplicate the full range of types of Pleistocene
marine limestones. The marine deposits, from the sea towards the land are:
Sub-tidal deposits which accumulate below the sea, the foreshore beach
which develops at the edge of the sea, and the back-beach which develops
between the foreshore and the dunes. Generally, this is the same vertical
ascending order which is preserved in the rock due to progradation of the
beach over the subtidal deposits.