This is one of my favorite habitats.  Often variable in depth and water flow year to year these small streams are home to one of my favorite groups of wildlife-- Salamanders.  They also provide water and habitat for woodlands birds (Louisiana Waterthrush and Scarlet Tanager frequent this habitat.)  Many have a rocky bottom which supports crayfish, blacknose dace, and many other aquatic species.  The terrestrial banks of these streams hold salamanders of many types (I have found as many as seven species in one day in the above pictured stream), snakes, and invertebrates.  They are also good places to see geological formations as the water cuts through several layers of limestone or sandstone and carries material from other places in its current.  Because of this these woodland streams are a good place to start looking for fossils.