Coquina The Rock that Saved St Augustine Castillo de ...
Mar 19, 2018· As this weak acid soaked downward, it dissolved some of the calcium in the shells, producing calcium carbonate, which solidified in lower layers, much like how flowstone and stalactites are formed in caves. This material "glued" the shell fragments together into a porous type of limestone we now call coquina, which is Spanish for "tiny shell".