The slopes to the west of the tors are made up of the rocks that were deposited on top of the quartzite. This sequence of rocks shows that the environments of deposition alternated from shallow water sediments with trilobites and shallow water brachiopods to a deeper water environment in which there are other trilobites and where graptolites were much more common.

The steeply dipping Mytton Flags are a good source of fossils. Beds such as these contain graptolites and trilobites.