Snakeskin liverwort (Conocephalum conicum), like green tongues, climbing the wall of a coastal cave.
Also know as Great scented liverwort - because of its aroma, which I've heard resembles everything from citrus fruit to urine!!
I've been blessed with a poor sense of smell so fortunately I cannot confirm 🤣
County Antrim, Ireland.

Cormacscoast.com walking tours