The spring emerges directly from a band of Carboniferous Limestone made up of two series, Cefn Mawr and Minera.

These lie in a North/ South direction at right angles to Silurian shales to the north, faulting east west and Cefn Fedw Sandstone to the south also faulting east west. There is complete absence of drift over the limestone.



The Underlying Geology    :    The Hydrology    :    The Process