Most eastern rivers, Potomac and Shenandoah included, are littered with Indian fish traps. Many of which were later constructed by African slaves. The fish were driven down stream to the rock walled traps by drivers where others caught the fish in baskets as they fled through the only gap in the wall. They are today, great places that hold fish because of their bait-holding structure.… and to think- our ancestors caught fish with sticks and vines …