This is a bit off the wall a bit but with the spectacular success in the pre-salt of offshore Brazil and the flurry of activity in the W. African coastal pre-salt, one wonders when industry will look seriously at a similar play in North Louisiana and South Arkansas.

The areas are geologically similar, only separated in time by about 100 million years or so.  In the early Cretaceous the Atlantic began to open up, rift basins developed that were overlain by thick salt from periodic inflows and evaporation of seawater.  This provided the perfect seal for the pre-salt structures and graben filling lake deposits. 

Flash back to the Triassic when the Gulf of Mexico began opening, similar rift valleys opened, many were filled by the Eagle Mills formation.  Later influx and evaporation of seawater created the overlying Louann salt which has been considered  the "basement" for oil companies.  There have been a handful of pre-salt penetrations over the years, the most intriguing being the Union Producing 1-Tensas Delta, 8-22N-4E, that in 1940 drilled through 1200' of Pennsylvanian marine shale below the salt.  

Seismic data is problematic below the salt new processing techniques are beginning to overcome that.  That said, it was clear on 80's - 90's vintage data that huge structures were present.   One wonders if the big boys will ever take a new look?