Coquina shells are tiny and numerous and can be seen all along the Florida coastline. These are the tiny shells you may see quickly digging into the sand as the surf receded from the beach. The beach seemingly comes alive as the tiny Coquina quickly cover themselves over and over. The sea birds eat them, and it looks to me like the shells are in a constant game of hide and seek – for their life!
It’s quite amazing that these little shells, when grouped together, make up a material which is hard enough to be used to build a structure, much less a huge fort! But that is what the historical Castillo de San Marcos fort in St. Augustine, Florida was made from. Yes, the basic material for those big walls is tiny seashells!