The maritime approach to Peggy's Cove reveals what road visitors never see: a granite archipelago sculpted by 12,000 years of post-glacial erosion, where basalt dykes slice through pink feldspar and the Atlantic carves notches into stone at a rate of three millimetres per century. Boat departures from Halifax Harbour trace the same shipping lanes that carried rum runners during Prohibition and Grand Banks schooners bound for the cod fishery, passing McNabs Island's fortifications and the outer battery at Point Pleasant before rounding Chebucto Head into open water. Peggy's Cove Lighthouse, commissioned in 1915 to guide coastal traffic through St. Margarets Bay, stands 15 metres above mean high tide on a wave-washed promontory that receives fewer than 40 ice-free days per winter. The structure replaced an earlier wooden tower destroyed in the 1913 storm that claimed 27 vessels along the South Shore. Its octagonal concrete form, painted in the distinctive red-and-white daymark pattern adopted by the Canadian Coast Guard in 1967, remains an active aid to navigation serving the inshore lobster fleet and seasonal yacht traffic between Halifax and Lunenburg. Maritime boat excursions reveal the ecological transition zone where the cold Labrador Current meets the Gulf Stream, creating nutrient upwellings that support minke whale migrations between June and October, harbour seal colonies on offshore ledges, and seabird nesting grounds that host storm petrels, razorbills, and Arctic terns. The submarine topography drops from 20 metres at the inner bay to 60 metres at the outer shoals, where kelp forests anchor to granite erratics left by the Wisconsinan ice sheet. Nineteenth-century fishing villages along this coast—Indian Harbour, Glen Margaret, Hackett's Cove—developed around natural harbours protected by barrier islands and sustained by cod, haddock, and mackerel stocks that supported a population density greater than the interior highlands. The coastal route passes through a geological contact zone where the Meguma Supergroup's metamorphic slates meet the South Mountain Batholith's intrusive granite, a boundary visible in roadcuts and cliff faces where folded schist layers tilt at 70-degree angles. This same granite, quarried from nearby Prospect and Sambro, built Halifax's Victorian-era waterfront and provided ballast for transatlantic timber ships returning to Liverpool and Bristol in the 1850s.