Dimples, pimples and wrinkles

Rugged beauty on the face of stone.

Dimples

I think these little hollows are caused by pockets of softer material in the sandstone (called upclasts) which has washed away over time – but also could be where grit or small pebbles have been caught in a hollow and washed around, abrading the surrounding stone into a ‘dimple’ or hollow.

Pimples

The surface of this boulder of sandstone is pimpled, little swollen mounds protruding from the surface – they appear where the stone is covered in a crust of iron-ore and must have been shaped millions of years ago as the minerals settled in the sediment.

and Wrinkles

The ‘wrinkles’ in this block are again formed in the iron-band on the surface of the stone and are just like the bark of a tree.  Perhaps organic matter lay under the water and was covered by the sediment as it fell, which took an imprint of the bark, stem or wood (or whatever it is).  These fossilised creases and fissures are as crisp and clear as if they were the real thing.