It is here that the river enters upon the limestone outcrop; the first few boulders of this distinctive grey/white rock appear in the river bed amongst the myriad red/browns of the Old Red Sandstone. Soon the river's flow will be all but gone, swallowed by the cave sytsem beneath.
Uploaded to Geograph by Alan Bowring on 8 September 2012
Photo © Alan Bowring, 8 September 2012. Licensed for reuse under this Creative Commons licence