sentences:  Covering an area of 28 000 km² around with a length of 32 km long and 25 km wide, the Plain of the Cul-de-Sac is bounded to the north and south by high mountains and to the west by the Gulf of Gonâve on edges of which is the Haitian capital of Port-au-Prince and to the Plaine de l'Arcahaie that extends to the west.The Plain of the Cul-de-Sac extends eastward into the Dominican Republic.This valley was once an arm of the sea and upon withdrawal of the latter during the uprising Oligocene Miocene, salt water was trapped in the lowest points of depression resulting in two grand lakes; the Etang Saumâtre (also called "Lake Azuéi") in Haiti and Lake Enriquillo in the Dominican Republic and a small freshwater pond called Trou Caïman, also in Haiti.