Moor Mill Quarry, West is a geological

Site of Special Scientific Interest A Site of Special Scientific Interest (SSSI) in Great Britain or an Area of Special Scientific Interest (ASSI) in the Isle of Man and Northern Ireland is a conservation designation denoting a protected area in the United Kingdom and Isle of ...

How Wood How Wood is a residential village, south of Park Street village between the towns of Watford and St Albans in St Stephen civil parish, Hertfordshire, England. The district council (in this instance, mid-tier of local government) is the City and ...

Hertfordshire Hertfordshire ( or ; often abbreviated Herts) is one of the home counties in southern England. It borders Bedfordshire and Cambridgeshire to the north, Essex to the east, Greater London to the south, and Buckinghamshire to the west. For govern ...

. The local planning authority is

St Albans City and District Council ST, St, or St. may refer to: Arts and entertainment * Stanza, in poetry * Suicidal Tendencies, an American heavy metal/hardcore punk band * Star Trek, a science-fiction media franchise * Summa Theologica, a compendium of Catholic philosophy an ...

. It was notified in 1992 as representing the former Moor Mill Quarry SSSI, which was lost to landfill operations. It is listed by the

Geological Conservation Review The Geological Conservation Review (GCR) is produced by the UK's Joint Nature Conservation Committee and is designed to identify those sites of national and international importance needed to show all the key scientific elements of the geological a ...

. The pit shows a sequence of

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

Anglian and pre-Anglian deposits. It displays an early blocking of the pre-Anglian

Thames Valley The Thames Valley is an informally-defined sub-region of South East England, centred on the River Thames west of London, with Oxford as a major centre. Its boundaries vary with context. The area is a major tourist destination and economic hub, ...

, at a time when the

River Thames The River Thames ( ), known alternatively in parts as the The Isis, River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the Longest rivers of the United Kingdom, se ...

followed a more northerly course, resulting in the formation of a lake. This was overrun by a second advance of ice during the Anglian glaciation around 450,000 years ago, which diverted the Thames to its present course and initiated

Colne Colne () is a market town and civil parish in the Borough of Pendle in Lancashire, England. Located northeast of Nelson, north-east of Burnley, east of Preston and west of Leeds. The town should not be confused with the unrelated Colne Val ...

drainage in the area. The site is regarded by

Natural England Natural England is a non-departmental public body in the United Kingdom sponsored by the Department for Environment, Food and Rural Affairs. It is responsible for ensuring that England's natural environment, including its land, flora and fauna, ...

as of fundamental importance as the only one which demonstrates the diversion of the Thames from its pre-Anglian course. There is no access to the deep quarry, which is partly filled with water, but it can be viewed by crossing the railway line at How Wood station and turning south to follow the east side of the

Abbey Line The Abbey Line, also called the St Albans Abbey branch line, is a railway line from Watford Junction to St Albans Abbey. The route passes through town and countryside in the county of Hertfordshire, just outside the boundaries of the Oyster Car ...

See also

References

Further reading