There is lots of speculation about it's origin, but its purpose is clear. It acted as a marker for sailing ships to navigate to a point where they could harvest salt, an essential commodity to the crew’s survival for long voyages. For thousands of years, prior to refrigeration, salt was the only element that would allow food (fish, meats) to be stored for long periods without spoiling. Hence it was essential to any voyage of substantial duration.
The Hermitage Estate in William's Town, Little Exuma, is a 970-acre cotton plantation, on the grounds of which stands the Cotton House, the oldest building in The Exuma’s. It was originally built in the 1750s by loyalists fleeing America.