The building consists of an unusually diverse array of building stones, as the two images below show. The origin of these stones is also unusual: they were transported from afar as ballast in the holds of sailing ships arriving in Savannah. Ships coming with little or no load would have previously taken on stones as ballast, and they would dump those stones as they took on loads in Savannah. These stones, probably from Africa or the Caribbean, were valuable building resources, because the sources of solid rock nearest Savannah are many miles inland across the sandy Coastal Plain. More ballast stone can be seen in the retaining wall at the left and in the cobblestones below.