undifferentiated rock units

Paleontology and geology

During the Cambrian, the land that is now Alabama lay south of the Earth’s equator along the edge of the Iapetus Ocean. Rising sea levels during the Late Cambrian produced a thick sequence of sedimentary rocks that contain a smattering of marine life, including fossils of trilobites and brachiopods. Although not shown on this map, rocks formed from these marine sediments can be found across parts of northern Alabama.