Plato says that a survivor of the great flood named Poseidon was granted an allotment of the earth. He married a human woman and had ten sons. The oldest son Atlas was given the central portion of the land. The capital of the ten nations was placed in the heart of Atlas’ nation. This capital was named after Poseidon. Plato goes into some wonderful detail about a ringed citadel within this massive capital. I included some of the buildings and temples in Second Sight that Plato described including the baths and the temple with the bulls.
I have drawn Atlas with none of the borders reaching the coastlines. Josephus says that ancient peoples were too afraid to live near the coasts after the flood. It appears Poseidon was determined to give his eldest son the most protected spot in his empire. Atlas would have been protected by two mountain chains, the mountains to the east that are now submerged and form the windward islands of the Caribbean and the mountains to the west that edge the west coast of central America.
Atlas is shown in pale purple. Poseidon is shown in pale red. The Citadel is shown in brighter red. I base the location of the Citadel from a compass reading I took in Peru showing an east of magnetic north deviation that went directly over the Caribbean. The vertical line on the map is that orientation reading. The compass reading was taken at an ancient land carving called el Candelabro. I made the overlays transparent so you could compare modern coastlines to ancient coastlines.
Hope this is of interest and sparks further study and exploration.
All the best,