The third zone is the central backswamp area of the delta, crossed by old creek levees.    From Wordnik.com.  [Niger Delta swamp forests] Reference

Like other backswamp regions, soils generally contain considerable organic matter and have substrates of massive clay.    From Wordnik.com.  [Ecoregions of the Mississippi Alluvial Plain (EPA)] Reference

Agriculture is not prevalent in this region, and many of the larger blocks of backswamp still support bottomland forests.    From Wordnik.com.  [Ecoregions of the Mississippi Alluvial Plain (EPA)] Reference

The backswamp areas are very important for processing excess nutrients found in the water and detaining water after heavy rains.    From Wordnik.com.  [Ecoregions of the Mississippi Alluvial Plain (EPA)] Reference

The Grand Prairie ecoregion has a thick veneer of loess deposits covering silty and clayey deposits of old Mississippi River backswamp.    From Wordnik.com.  [Ecoregions of the Mississippi Alluvial Plain (EPA)] Reference

This and the sandy veneer of natural levee deposits allow ecoregion 73i to be farmed more easily than other backswamp ecoregions (i.e. 73d and 73m) of the Mississippi Alluvial Plain (73).    From Wordnik.com.  [Ecoregions of the Mississippi Alluvial Plain (EPA)] Reference