The next deposits, as the scarps are approached, are greensands of "Selbornian" age, succeeded by Cenomanian, and locally by Turonian, sands.
During the current cycle of erosion, several of the faults, whose scarps had been worn away in the previous cycle, have been brought to light again as topographic features by the removal of the weak strata along one side of the fault line, leaving the harder strata on the other side in relief; such scarps are known as fault-line scarps, in distinction from the original fault scarps.
These rocks are much folded and the shales are locally cleaved into slates, while the sandstones and conglomerates form scarps and ridges.
The southern edge of the county is formed by the scarps and moorlands of the Carboniferous Limestone and Millstone Grit (both of which form also the outlier of Pen-ceryg-calch north of Crickhowell), while the lowest beds of the Coal Measures of the South Wales coalfield are reached in the Tawe and Neath valleys (where the beds are much folded) and near Tredegar and Brynmawr.
The lower basin portion of Utah is separated from the high plateaus by a series of great fault scarps, by which one descends abruptly to a level of but 5000 or 6000 ft.
