The name itself is more description than designation, pointing to the fragile, shifting character of ground that sits at the boundary between land and sea, shaped less by geology than by the slow accumulation and redistribution of sediment over time. Such formations along the west Mayo coastline have long existed in an ambiguous category, too insubstantial to develop, too present to ignore, and occasionally significant enough to attract the attention of those who recorded the archaeological landscape of the region.

The islands are listed as a monument within the Irish archaeological record, which places them in the company of sites deemed to have some historical or cultural significance, though the precise nature of that significance remains incompletely documented in the public domain. The west of Ireland coastline has yielded evidence of early human activity in similarly marginal environments, from shell middens to the traces of seasonal occupation by fishing and farming communities who worked the intertidal zone long before modern land boundaries made such places seem peripheral. Whether the Sand Islands at Cartron hold material from any particular period is not currently established in available sources, but the fact of their classification suggests something warranted a closer look at some point.