Pirates gold

Magnificent is this island,
Pummeled by the waves,
A forest of twisted trees flow to the island edge,
Rocks heavy with iron fall in to the abyss,
To the darkness below,
Darkness hides walls dripping like wax,
Standing water leads to a grotto filled with chambers,
On the walls pictograms to be deciphered to find untold riches,
Left by pirates in the golden age,
In the chamber X marked the spot,
Plunder stacked high a light in the dark