How to Identify Plants on Shoreline Old Coral

Not exactly underwater but close. I have some shots of plant (?) growth along the ironshore of Grand Cayman. There is very little tide so I assume these are exposed all the time except for wave action.

So looking for help in two areas:

• Anyone have any idea what this is?
• How do you classify these so I can look them up? Obviously not something you'd find in Humann & DeLoach.

Thanks

I would classify them as intertidal algae and search for that.

One might be Padina pavonica or close (https://en.wikipedia.org/wiki/Padina_pavonica)

The other sure looks like some type of Red Algae (Amphiroa), but there are so many varieties...

Good luck

Thanks bmorescuba. Your link provided an additional insight. I believe these are in the 'Littoral zone' of the shore. I was incorrect in the Cayman tides. They exist so there is a high/low water mark.