Along its length, Chott el Fejej never widens beyond 20 miles (32 km) and in many places is considerably more narrow.

[3] It was this narrow sandy ridge, separating the Chott el Fejej from the Mediterranean Sea, which brought it to the attention of various geographers, engineers and diplomats.

These figures looked to create an inland "Sahara Sea" by channelling the waters of the Mediterranean into Sahara Desert basins which lay below sea level.

A noted proposal to this effect was put forward in the late 1800s by French geographer François Élie Roudaire and the creator of the Suez Canal, Ferdinand de Lesseps, but stalled after the French government withdrew funding.

This anticline and other surrounding structures are argued to be the result of rifting in the Cretaceous period.