Leader: Joe Marx
Members $33; nonmembers $46
Riley’s Lock, on the C&O Canal in Maryland, is located adjacent to Seneca Creek at its junction with the Potomac River. The site presents great geological interest. Downstream on the Potomac is an upland block of hard Piedmont rock, part of the bedrock of the Pangean supercontinent. Upstream is soft sedimentary rock that was deposited in a rift valley connected with the opening of the central North Atlantic basin during the initial fracturing of Pangea. In addition, the ruins of the quarry that supplied the red exterior of the original Smithsonian building on the National Mall are closeby the lock and accessible. We will hike a couple of miles on flat terrain, both on the C&O Canal Towpath and on several more muddy and rocky side trails.  Note that our geology hikes move at a faster pace than our usual naturalist’s shuffle. REGISTER