More information: http://en.wikipedia.org/wiki/Dragon_Hill,_Uffington
Dragon Hill is a natural chalk hill with an artificial flat-top (situated on the scarp slope of White Horse Hill), to which clings the legend that it was on its summit that Saint George slew the dragon. A bare patch of chalk upon which no grass will grow is purported to be where the dragon's blood spilled. It has been suggested as some sort of Iron Age ritual site associated with the nearby hill-figure.