remains on the river, just south of Centerville. A large village occupied the town of Cahaba site from 100 to 1550 AD, during the Woodland and Mississippian periods. The town of Cahaba The Cahaba River ends at the former town of Cahaba, also known as Cahawba, or Old Cahawba. The town of Cahaba was Alabama's first seat of government from 1820 to 1825. William Wyatt Bibb, Alabama's first governor, decided on Cahaba because of the scenery, fertile area, and navigable river ways. Cahaba suffered harsh economic struggles and disease from 1819 to 1822. However, in 1821, a steamboat, the Harriet, overcame the Alabama River's fast current and made it past Cahaba. The river became a major trade route, which caused the city to grow, despite the removal of the capital to Tuscaloosa in 1825. Cahaba is now an abandoned town and a state historical site, administered by the Alabama Historical Commission. Geology The Ridge and Valley region of Alabama, which is where the Cahaba River begins, was formed when the African Plate collided with the North American Plate in the Paleozoic era. The valley soils consist of gravel, sand, and clay, while the ridges consist of chert and sandstone. The upper Cahaba region contains Cenozoic-era gravel, clay, and sand. In the lower Cahaba region, the soils are calcareous, or chalky. Ecology The waters of the Cahaba are home to more than 131 species of freshwater fishes (18 of which have been found in no other river system), 40 species of mussels, and 35 species of snails. The river has more fish species than can be found in all bodies of water in California. Sixty-nine of these animal species are endangered. The endemic freshwater snail Elimia cahawbensis is named after the river. One species long thought to be extinct, Leptoxis compacta, the Oblong rocksnail, was rediscovered in the Cahaba in 2011. Due to damming for hydropower, pollution, transportation, and erosion, it has suffered losses of species. Almost a quarter of the original documented mussel species in the Cahaba have disappeared with similar trends in the fish and snail numbers of species. Many species have still been discovered and rediscovered in and on the surrounding region of the river. The Cahaba is also home to 13 snail species not found anywhere else in the world. In the early 21st century, a Georgia botanist Jim Allison discovered eight unknown flower species, and later