Mount's Bay

Mount’s Bay stretches along the south coast of Cornwall from the Lizard Point to Gwennap Head, its half-moon curve sheltered from Atlantic westerlies though still exposed to southerly gales. The bay’s name comes from St Michael’s Mount, the tidal island near Marazion that rises sharply from the water. In winter the bay can be treacherous, with more than 150 known wrecks from the 19th century lying beneath its surface. The eastern side around Marazion and St Michael’s Mount was recognised in 2016 as a Marine Conservation Zone to protect fragile habitats. The coast alternates between steep schist cliffs, softer greywacke slopes and sandy beaches such as Praa Sands and Kenneggy. The bay’s geology tells a story of rising and falling seas over thousands of years. Raised beaches at Marazion show where the shore stood higher in past interglacial periods. At low tide near Penzance, partially fossilised tree trunks appear, remnants of a forest that grew from 6,000 to 4,000 years ago before the sea drowned it. Divers have recovered submerged tree trunks across the bay floor, some dating back to the Mesolithic period. Loe Pool, Cornwall’s largest lake, formed when a shingle bar dammed the River Cober, its pebbles carried from sources over 190 kilometres away. The Marine Conservation Zone shelters seagrass beds that shelter young fish and stalked jellyfish such as Lucernariopsis cruxmelitensis. Visitors walk the promenade in Penzance or follow the coastal path from Mousehole to Lamorna Cove. St Michael’s Mount can be reached on foot at low tide or by boat when the tide is in. Small coves like Kynance and Mullion Cove offer quiet swimming spots between rugged cliffs. Praa Sands and Porthleven Sands provide wide stretches of sand backed by dunes, while Marazion’s beach links the town to the island’s causeway. The Marine Conservation Zone’s tidal reefs and seagrass meadows lie just offshore, visible from boat trips or the shore at Perranuthnoe.