Water Under the Bridge

I’m positive this is all natural straining, but can you see the semi-stylized horse image? Somewhat reminiscent the animals in the Spanish Cave Paintings, it is developing on the wall under the Tooway Creek Bridge, at Moffat’s Beach. Water on the bridges is obviously leaching out calcium, salt and some iron but the black oxide straining is very typical of all the exposed rocks along the coast here and I suspect it maybe manganese and possibly has an algal or bacterial component. Whatever the staining is it is it is creating a pretty remarkable piece of art.