The tributary valleys that were composed of more resistant rock then hangs over the main valley.

The massif is built mostly by gabbro rocks, a hard and resistant rock.

This is the resistant rock now exposed at the bottom of the canyon in the Inner Gorge.

An entire lush environment was capped in a matter of minutes with 20 feet of extremely resistant rock, rhyolite.

Aubrey reported to him that they had encountered less resistant rock and that they were now 2000 feet away from the cave.

Buttes are formed by erosion when hard caprock overlies a layer of less resistant rock that is eventually worn away.

The caprock provides protection for the less resistant rock below from wind abrasion which leaves it standing isolated.

Then erosion set in, shaping more resistant rock into ridges and cutting valleys into weaker ones.

These are found where more readily weathered and eroded rocks occur surrounded by resistant rocks.

The coastline is composed mainly of resistant rocks that give rise in many places to impressive cliffs.