Geograph - photograph every grid square

I was mystified by this isolated wetland without any obvious inlet or outlet, but subsequent reference to the geological map shows that it is identified by the British Geological Survey as a kettle hole, and there is another just to the west. A kettle hole originates as a block of stagnant ice in deposits of till, which when melted creates a void which fills with water and mobile sediment. As the formation is likely to be clay-rich they are well-sealed, excellent ponds. Mynydd Anelog forms the distant skyline.