The north face of Pen Hill has a number of rock exposures where some quite extensive quarrying has been undertaken in the past. The sunken road seen in this image was presumably used to access the workings; curiously it's not marked on current (2014) OS maps.
Uploaded to Geograph by Trevor Littlewood on 3 October 2014
Photo © Trevor Littlewood, 3 October 2014. Licensed for reuse under this Creative Commons licence