Bayou-Diversity (8 April 2018) The Civil War citadel of Vicksburg fell on July 4, 1863. On that day Confederate regiments marched out one at a time and stacked their arms. Of that occasion, General Grant’s telegraph operator, Samuel Beckwith, wrote, “The tramping of myriads of feet had stirred up a fine, yellow clay dust that coated our garments and filled our eyes and ears and nostrils until it was almost unbearable.” Like the Union soldiers, this dust had origins far to the north of the Vicksburg hills.
The geologic term for the soil type is loess (pronounced low-ess). It is strikingly noticeable on the deep road-cuts along I-20 in Vicksburg. Most of our soils in this region were deposited by waters of ancient seas or meandering rivers, but the loess soil by definition came on north winds. As ancient glaciers lumbered south into the middle of North America they ground the bedrock into fine flour-like soil. When the glaciers retreated, the tiny particles washed into floodplains where strong winds scoured the surface and picked them up to be deposited a second time on the Vicksburg bluffs and nearby areas. The Sicily Island hills are capped with thirty feet of loess. Thinner sheets deposited at different times drape the Bastrop Hills, Macon Ridge, and scattered areas in the Ouachita River floodplain. The only other place in the world with as much of the same type soil is in China.
During the 47-day Vicksburg siege, the town was relentlessly shelled by Union gunboats and artillery. To survive, many citizens became miners, burrowing into the soft hills to construct cave shelters, often quite elaborate and equipped with the finest carpets and furniture. Some were described as capable of accommodating 200 people; others were small and sparse. Considering that digging functional caves would have been nearly impossible if the hills had been composed of the black gumbo soils just across the river in Louisiana, or even the red clay soils east of town, the loess with origins near the Yankees’ Midwest homes may have saved lives during this grim historical episode. ©KO