The high ground between the trees is the depleted motte of Castle Toll,which was constructed within the boundaries of a more ancient site,believed by many,to be the site of the Saxon burh of Eorpeburnan.One of the main problems in identifying Saxon sites,is name changes over the centuries,and no definitive Saxon map showing where sites were.
see http://www.castlefacts.info/castledetails/castleDetails3.aspx?uin=11601
see http://www.fortifiedengland.com/Home/Categories/ViewItem/tabid/61/Default.aspx?IID=2764
see http://www.pastscape.org.uk/hob.aspx?hob_id=417477