Kearny Marsh is a freshwater marsh contained within a 310-acre impoundment of roads and railbeds. Incidental impoundment ponds are especially heavy in this part of the Meadowlands, formed by the random crisscrossing trajectories of pipelines, rail lines, roadways, landfills, on-ramps, and berms. Each pond is its own anonymous ecotonic soup. In other cases nearby triangular voids are marsh that has been filled in and developed into Walmarts, postal processing centers, and scrap yards.