Why go
The contrast between the central hills and the lower Terres Basses peninsula is more than scenery. Volcanic activity, coral growth and changing sea levels all helped build the island. Pointe Blanche, Tintamarre and Baie Rouge offer named reference points for understanding why its rocks and shoreline take such different forms.
The full story
Saint Martin formed through a long interaction between volcanic activity and the sea. Volcanoes raised material toward the surface, allowing coral reefs to develop on the submerged Anguilla Bank. Their growth added limestone, while later volcanic intrusions helped form the central hills. The island’s high ground and carbonate formations therefore preserve different parts of that history. Layered limestone occurs at Pointe Blanche. Tintamarre has marine fossils and gypsum crystals, while the lower Terres Basses peninsula is linked to the rest of Saint Martin by coastal sand barriers. Those sandy connections are younger features and continue to change. Sea levels repeatedly altered the coastline. During periods of lower water, Saint Martin, Anguilla and Saint-Barthélemy were connected across their shared submarine bank. Around the present coast, the pierced cliff at Baie Rouge gives a visible example of rock shaped into a distinctive shoreline. At Pointe Arago, pillow lavas record molten rock cooling beneath the sea.