Areas of Crag are rocky and hard, sometimes with some plant growth but more often looking rather barren. Looks can be deceiving, though, as these places often have cave systems, and small nooks and crannies that can host a plethora of life hidden from view.
Photo by Allan Carvalho: https://www.pexels.com/photo/a-reef-underwater-in-black-and-white-17403377/