Mousehold Heath is a 184-acre (74 ha) public area of heathland, woodland and recreational open space to be found to the north of Norwich city centre. It is the largest of the nature reserves managed by Norwich City Council. It was once an extensive area of heathland that stretched for several miles to the north and east of Norwich, but has since been largely converted to woods and farmland.
St. James' Pit, Mousehold Heath
The landscape of Mousehold Heath (as it was before enclosure occurred at the beginning of the nineteenth century) is part of a outwash plain created by fluvial processes. The geology of the area is complex, consisting of a set of vertical layers of glacial deposits from the Anglian Stage resting on a bedrock of Cretaceous chalk and the Norwich Crag Formation.
Chalk was deposited 75 million years ago, when the area was part of a warm, tropical sea. The chalk is now exposed near the southern tip of the heath at St James' Pit, which is an 8.6-acre (3.5 ha) geological Site of Special Scientific Interest and Geological Conservation Review site. About two million years ago sands, gravels, quartz pebbles and clays were deposited across the area of Norfolk that now includes the heath. Similar materials were deposited during a glacial period that occurred more than 475,000 years ago. Clay, sand and gravel was laid over Mousehold Heath about 425,000 years ago, caused by the movement of melted ice. The heath's present landscape was more recently formed as a result of erosion, caused by streams cutting through the soft rocks. It later became altered when silts were blown over the topsoil, when the ground churned as a result of temperature variations and when sludge layers moved downhill during warmer seasons.
Detailed information about the geological history of the present Mousehold Heath, in the form of a ‘Heritage Trail’ leaflet and accompanying notes for points around the trail, has been produced by Norwich City Council.