GeoGraph - photograph every grid square

The pool shown on the 25K map coincides with this flat marshy area - a case of vegetational succession perhaps? Certainly the water table was high at the time of my visit so it ought to have been there. Bedrock lies at or within centimetres of the surface over much of this landscape so drainage is pretty much at the surface, other than where solutional collapse of underlying limestone has taken place and allowed sinkholes to form in the gritstone capping.