I saw a weird pattern in the bricks at an old fort in St. Augustine

Mia Gonzalez · 2026-03-10T19:00:05.273833+00:00

I was walking around the Castillo de San Marcos last month and noticed some of the coquina bricks have these deep, perfectly round holes in them. They're not from cannonballs, they look drilled. A park ranger said they're from some kind of core sampling done in the 1950s, but he didn't know why they picked those specific spots. It made me wonder what they were looking for and if they ever published the results. Has anyone else seen these or read about that study?

spencer_kim857mo ago

Maybe they were just really bad at playing connect the dots.

4

the_wendy7mo ago

That core sampling detail is so cool! I bet they were checking for salt damage or something, since coquina is so porous.

3

river_murphy7mo ago

Actually, coquina is porous, but that's why it's so good against cannonballs (it absorbs the impact).

1