We will take a trip (Location TBD at a later date) into the beautiful southern half of the Cahaba River watershed. Below Centreville, the Cahaba River is much wider and more meandering than the stretches in the central and northern regions of the watershed. Late Cretaceous melting of ice caps led to what is known as the Mississippi Embayment, a shallow sea that covered much of the southeastern US. As these waters receded they left behind soils that were much sandier and more easily eroded. The edge of this 65 million year old sea is called the "Fall Line" in Alabama. It is the boundary between the harder rocks of the Appalachian Highlands and the softer soils of the Coastal Plain. As the Cahaba River reaches these soft soils in the Coastal Plain, it is able to stretch and meander across the landscape more easily, leading to a wider river.