The Coquina rocks at Washington Oaks is part of the Anastasia formation, which stretches from St. Augustine to Palm Beach County, and was created during the Pleistocene era (12,000 - 2.5 million years ago). During that era when sea level was lower, shells and sand were exposed to rain.

Where is coquina formed?

Most coquina-forming sediments are found in tropical or subtropical marine waters because that is where an abundant supply of fossil debris is most likely to be produced. They usually form along ocean beaches, barrier islands, shallow offshore bars, or tidal channels.

Is coquina man made?

Coquina is also the name of a common tiny clam found everywhere on Florida beaches. Their shells, which come in countless colors, are reflected in the Castillo's muted hues. ... A related building material is tabby, often called coastal concrete, which is basically manmade coquina.