Quarry Historical Site

Coquina rock links Anastasia Island to the charismatic architecture and history of St. Augustine. More than 300 years ago, Native American Indians, enslaved Africans, and the Spanish worked coquina quarries of Anastasia Island to construct the Castillo de San Marcos fortress. In Anastasia State Park you may take a short walk down a shaded and signed trail to view the site of these labors.

When the quarries were active, St. Augustine (founded in 1565) was a struggling outpost of Spain’s American empire. Spanish soldiers built their homes and forts out of local pine, palm, and palmetto, but these wooden settlements were repeatedly destroyed or burned by pirates and raiders. Soon the Spanish discovered a better building material on Anastasia Island: coquina rock.

Acquisition of coquina rock was difficult, but resulted in durable and solid buildings. The workers hewed out squares of the relatively soft, wet stone with hand-tools and loaded them onto carts. Oxen dragged these heavy loads to the water, where the blocks were barged across Matanzas Bay to the town of St. Augustine.

Finally, in 1671, large-scale quarrying began in the stone pits. Anastasia Island was even called "Cantera", Spanish for "quarry".

Early on, quarrying was limited by manpower, engineering skills, and money. In 1598 workers had cut out enough coquina blocks to build a gunpowder storage magazine. Finally, in 1671, the Spanish embarked on large-scale quarrying on Anastasia Island. At this time, the island was called “Cantera,” Spanish for quarry. Several historic quarry sites dot the island; one is easily visited in Anastasia State Park. The St. Augustine Amphitheatre sits in another.

The people of St. Augustine didn’t realize they had happened upon an amazing defensive material. As the soft stone was exposed to air, it hardened. The Spanish waterproofed coquina stone with plaster and paint, so the coarse rock structures you see today, such as the Castillo de San Marcos and city gates, would have looked more refined. However, when besieging ships bombarded the Castillo, the walls simply absorbed the cannon balls. The Castillo de San Marcos was never captured in battle, thanks in at least part to the rock made of tiny shells, coquina.

Spanish, British, and Americans in turn prized coquina as a building material and went to great lengths to obtain it. By the late 1700s, Native American Indian populations were decimated and the Spanish primarily employed enslaved Africans to work the quarries. The quarries were not exhausted and today some coquina is still quarried commercially.

Coquina rock is part of a sedimentary formation that underlies much of the Atlantic shore of Florida.

The story of coquina rock begins in West Africa, where a similar rock formation is found. Coquina forms a sedimentary structure underlying much of the Atlantic shore of Florida, and geologists believe eons ago, before the continents drifted apart, these formations were connected. Sand and Donax variabilis clam shells accumulated when sea levels were higher and the area was underwater. Later, during a glacial period about 125,000 – 100,000 years ago, the sea level dropped. Rain dissolved calcium carbonate from the shells, cementing the mix of quartz and shells together into coquina rock.

The word "coquina" means "tiny shell" in Spanish. It was the name they gave to the Donax variabilis clam that was abundant on the northeast Florida beaches. It is the predominant shell in the rock.

Remember that this area is a protected historic site on the National Register of Historic Places and nothing may be removed from it.