It ends in a waterfall consisting in a series of cascades, each between 0.5 and 1.5 metres high, that have formed due to the unequal hardness of the different beds of the underlying rock.
Whereas the rocks of the surrounding areas form part of the Bude Formation of the Upper Carboniferous, those in the Peppercombe are an outlier of a later, presumably Permian age.
These rocks extend for about 2 km inland, and consist of breccias with scattered calcareous bands and nodules, with occasional beds of sand and sandstone.
[3] This outlier is thought to be a remnant of the New Red Sandstone that formerly covered a much larger part of Devon, having been eroded away in geological times.
It is thought that these rocks are derived from sediment deposited by rainstorm floods in an otherwise dry desert area situated on the fringes of a rugged highland.