Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Black Belt is a region of the U.S. state of Alabama, and part of the larger Black Belt Region of the Southern United States, which stretches from Texas to Maryland. The term originally referred to the region underlain by a thin layer of rich, black topsoil developed atop the chalk of the Selma Group, a geologic unit dating to the Cretaceous Period. The soils have been developing continuously at least since the Pliocene Epoch. Because the underlying chalk is nearly impermeable to groundwater, the black soils tend to dry out during the summer. The natural vegetation of the chalk belt consisted mainly of oak-hickory forest interspersed with shortgrass prairie, while the sandy ridges flanking the chalk belt supported pine forest. For lack of a reliable source of water, the earliest settlers avoided farming the black soil until the discovery that deep artesian wells could be drilled to supply people, livestock, and crops. Beginning in the 1830s, cotton plantations became Alabama's greatest source of wealth.