This has always fascinated me as we live on the northern end of the escarpment and over the years we've been here, cycling and more latterly, running up and down the slopes has got me wondering the same thing. Without any true knowledge though, I would have personally thought it was a natural peak but are you suggesting that because of its height above the Thames valley, it might have been formed in antiquity? What about a Hill Fort? A lovely thought! And delighted to see the Myatts Fields market gardens still present, top left.