Not-so-secret secrets of the urban refuge

By Beth U. I like margins. Edges of scholarship, abandoned lots, wildlife preserves carved from the industrial grid. I often walk at Tinicum Refuge, a marshland adjacent to the Philadelphia Airport and the largest remaining freshwater tidal wetland in Pennsylvania. It is only because of conservationists’ efforts that Interstate 95 runs alongside the marsh rather than through it. Along the other side sits the Sun Oil Company tank farm, a series of enormous canisters that ...