The last kiln on Negro Mountain was abandoned about 1835. Kilns were used to extract pine tar from pitch pine. Dished stones like the one found just off South Wolf Rock Road formed the bases of tar kilns. Pitchy sections of resinous pine, including knots and cones, were stacked on these stones and then covered with earth and wet leaves. The stack was ignited, and the heat caused the pitch to ooze out of the pine onto the stone and run off along a collecting groove to where it was gathered.