Underneath the east coast of Florida lies the unique Anastasia limestone formation. Also known as coquina (the Spanish word for cockle bivalves), this rock is composed of shell fragments, coral bits, small marine fossils, and sand. It formed during the Pleistocene Epoch when the majority of Florida was covered by the ocean. Most of the formation is covered by soil and sand except for a large outcropping at Blowing Rocks Preserve near Hobe Sound.

Waves have sculpted the Anastasia limestone into burrows, pools, ledges, and the ubiquitous blowholes that give Blowing Rocks its name.

In addition to protecting this rare geological outcrop, Blowing Rocks Preserve also conserves several important Florida habitats like mangrove swamps, maritime hammocks, dunes, seagrape scrub, and portions of the Intracoastal lagoon. Just offshore, snorkelers and swimmers can also see the large honeycomb-like reefs of colonial, filter-feeding sabellarid worms.