This section of Delaware roughly corresponds to the boundaries of two historic New Castle County hundreds, embracing fertile agricultural land on the upper margin of the Coastal Plain. Along its southern edge runs the Chesapeake and Delaware Canal; at its northern rises a geological anomaly, Iron Hill, a mass of the dark, igneous rock called gabbro protruding above the soft silts and clays of the surrounding fields. For thousands of years, Iron Hill attracted Native Americans who quarried jasper on its slopes and established stone-tool workshops. European settlers mined the hill for iron ore from the early eighteenth century until about 1890. Historically, its greatest fame came during the British campaign for Philadelphia in 1777: General George Washington, Nathanael Greene, and the Marquis de Lafayette reconnoitered the advancing army of General William Howe from the summit, and the Battle of Cooch's Bridge raged at its base. Elsewhere in the region, prosperous farms and towns developed at an early date and grew gradually. In the twentieth century, the convulsive growth of the 1950s brought the construction of an enormous oil refinery in Red Lion Hundred. For its part, Pencader Hundred became the fastest-growing section of New Castle County, its population increasing by 259 percent that decade. The area has subsequently been overrun almost entirely by sprawl, eventually obliterating even the last surviving farms along the southernmost fringe. Many old farmhouses and outbuildings have been destroyed, including any surviving traces of the log house inhabited by the architect Benjamin Henry Latrobe on the summit of Iron Hill, where he lived in summer 1805 during construction of the Feeder Canal (part of the first, abortive attempt to build a ship canal across the peninsula). Latrobe's probable house site was developed for houses in 2000.