The states of arkansas, kentucky, missouri, and Tennessee are located in the central south region of the United States. They cover a vast area stretching from the Appalachian Mountains across the middle of the Mississippi River's course westward to the beginning of the Great Plains. Geologically, the central south region covers a diverse [Page 1824]topography of mountains, plateaus, hilly regions, and plains. Most of the region was submerged under shallow seas during several geological periods and is now covered in limestone rocks, which have eroded to make numerous caves in some areas and sweet soils for grass and crops.