The rocks in this area comprise light-colored weak sand and mudstones overlain by darker and harder volcanic ash and lava (basalt). The red staining seen on the sandstone is a result of iron staining.
The most notable feature in this area is the sandstone fluting, or curtains. This weak layer of rock is overlain by harder rock, protecting the top from eroding. After heavy rainstorms, water seeps out from between the layers and runs down the side, taking sand with it. Evidence of water seeps can be found even when dry. When the water evaporates, it leaves white, snow-like crystals made up of salt minerals on the surface.
The cliffs are all tilted at an angle of 17 degrees, due to intense faulting in the past 10 million years as the North American and Pacific plates slide past one another. Nearby is the Garlock fault, a left-lateral strike slip fault, that is thought capable of an earthquake and has registered 35 km of offset.