Primary seacoast lights warned mariners of their proximity to land, the presence of navigational dangers, and helped them set their course. By 1852, however, lighthouses and lightships often looked so much alike that distinguishing one from another was difficult. Each lighthouse therefore came to have a characteristic, or coded sequence of light flashes, that allowed mariners to identify the light and its location along the coast; for example, Barnegat Light flashed every ten seconds at each point of the compass. Lighthouse towers also had daymarks, distinctive designs and paint patterns, such as the yellow-black-yellow pattern on Absecon Lighthouse, which helped mariners tell it from others. Some lighthouses, especially those on dangerous shoals in harbors and bays, also used fog signals to warn mariners of potential danger. New Jersey’s lighthouses included Sandy Hook Lighthouse, Robbins Reef Lighthouse, Romer Shoal Lighthouse, Twin Lights of Navesink, Conover Beacon, Great Beds Lighthouse, Chapel Hill Lighthouse, Sea Girt Lighthouse, Barnegat Lighthouse, Absecon Lighthouse, Hereford Inlet Lighthouse, Cape May Point Lighthouse, East Point Lighthouse, Finns Point Rear Range Lighthouse, Brandywine Shoal Lighthouse, Elbow of Cross Ledge Lighthouse, Miah Maull Shoal Lighthouse, Ship John Shoal Lighthouse, and Tinicum Rear Range Lighthouse.