The island of Grand Cayman, in the western Caribbean, has an extensive mangrove swamp vegetation. Numerous cores have been taken in and adjacent to these swamplands, and these reveal that the swamps are generally underlain by a transgressive sequence of sediments. The basal unit of this sequence consists of a laminated or non-laminated crust, formed in a subaerial environment. Locally, these crusts are overlain by plastic mud, deposited in seasonally-flooded environments. Mangrove peat forms the upper unit of the transgression within most of the swamplands, overlying the other units where these are found, and reaching thicknesses of more than 4 m. The final stage of marine incursion is recorded to the east of North Sound, where, in water depths of 10-200 cm, shelly mud occurs overlying mangrove peat. In contrast to this, to the west of North Sound, there is a regressive sequence in which shelly marl underlies a localised sea grass peat and mangrove peat. This regressive sequence records local progradation of mangroves into marine environments. The transgressive sedimentary sequence on Grand Cayman is similar to transgressive sedimentary sequences described from the Florida Everglades-mangrove complex, Florida Bay and the Belize Shelf. On Grand Cayman, however, the stratigraphy is less complex because there are not extensive freshwater peat-forming environments, or intertidal and supratidal carbonate environments. Samples of mangrove peat were collected from the peat/bedrock interface along a surveyed profile across Barkers Peninsula on Grand Cayman Radiometric dating of these implies that sea level was approximately 185 cm below the present level at least 2100 years BP. Comparison of these dates with dates on mangrove peat from elsewhere suggests that submergence on Grand Cayman has taken place at a similar rate to that in Florida. © 1981.