There are four major seas mentioned in the Book of Mormon: North, South, East, and West; and two minor seas: Sea that Divides the Land and Ablom. More information about those seas can be found on the Seas page. The four major seas are not a metaphor, and the Sea South was not south of all Book of Mormon lands; only Jaredite lands. If a model does not respect the clear reading of the text, it must be discarded.
Book of Mormon events took place over 1600 years ago and there were significant land changes that occurred with the coming of Jesus (all of which IS accounted for on this site). As a result of the land being split and lifted—as prophesied, the inlet for the Sea South was nearly cut off and its volume of water largely evacuated in the great deluge. Since then, its size has greatly diminished through evaporation the last 1600 years. Remnants of it however can still be seen at Tonawanda State Wildlife Management Area, the Iroquois National Wildlife Refuge, Oak Orchard State Wildlife Management Area, and Bergen-Byron Swamp.