As you walk along the rocky shoreline of Great Stirrup Cay, look down to appreciate its geological evolution. The island’s formation began about 300 to 400 million years ago during the tectonic shift of North America away from Africa. In the Jurassic era, about 160 million years ago, dead marine life began building up as sentiment. These deposits formed into oolite, a substance used in cement and glass making. Within the last 900,000 to 120 years, this material became reefs and then the mass emerged from the sea as islands. A close inspection will reveal fossilized shells and tiny skeletons. This historical evidence is more pronounced during extreme low tides when the sea floor can be exposed for miles at the south end of the island.
