We have divided the county into seven regions as a practical way of describing the landscape. We are working in each region to highlight sites that represent the local geology of the area. We are also developing trails that link some of these sites with places of historical and cultural interest as well as with other walking routes. We try to work in partnership with local communities to enable geology and landscape to be included in their own heritage projects.
Cambridgeshire is known for its fenland landscape, a unique area of extensive low-lying land that has been formed by a complex, dynamic and rich geological history. Clues to this history, can be found by studying the surprisingly diverse deposits that remain, including sands and gravels from the last 2-3 million years or so (the Quaternary Period), as well as freshwater peat, tidal flat sediments and river alluvium deposited in the years since the last ice age (Holocene) and it is these that give such a distinctive character to much of the north of the county, lying in the extensive fen basin and below sea level in some places.
The transition from the low lying fens to the surrounding ‘highland’ forms a significantly important cultural area, the fen edge, with characteristic landscape features of its own. Less well known to most people, and in some ways less distinctive, are the ‘claylands’ that form much of the central band of the county on the fen edge and underlie much of the fenland in the north. Yet these clays, mostly Jurassic, and their associated sediments have some of the richest fossil deposits in the country, a few of which have become famous worldwide. Among the clays lie deposits of sandstone giving the county a small area of sandy heath, an extension of the Greensand Ridge that runs through Bedfordshire.
The chalk escarpment that forms the southern part of the county dates from the Cretaceous and provides Cambridgeshire with a share of England’s chalk downland, extending as the Chilterns to the south west and the Yorkshire Wolds in the north of the country. The valley of the River Cam, lying to the north of the escarpment, receives much of its water from chalk springs that line the scarp slope. Two major rivers cross the county, the Ouse and the Nene, both of which now have extensive ‘washlands’ that are of high value to nature conservation. Their courses have changed dramatically over their lifetime creating many of the present day landscape features. Forming much of the Nene Valley in the northwest of the county are Jurassic formations that contain the famous limestones from which many of the important local buildings have been formed, including the cathedrals at Ely and Peterborough. They are part of the Jurassic sequence that extends south as the Cotswolds and north into Yorkshire.
Finally, over much of the county, particularly in the south, lie ice age deposits from the last 2-3 million years, most of which form higher land including a distinctive ‘high’ plateau, famous for its ‘boulder clay’ woodlands, between the Cam and Ouse valleys to the west of Cambridge,
Local Geological Sites (LGS) in Cambridgeshire
Previously called RIGS (Regionally Important Geological Sites) and also referred to as Geosites, Local Geological Sites need to be considered within the planning system. Our Geosites initiative was launched at the beginning of 2010 with one of its main aims being to obtain LGS designation for sites in the county that are of geological interest for their scientific, educational, historical or aesthetic value. We are working in each of the landscape regions to designate important sites as LGS. Many of these sites are likely to have public access and can be used by community groups and the general public to enjoy discovering their local landscape.
The Mapping of Landscapes, Geology and Soils of Bedfordshire and Cambridgeshire
By Timothy Farewell, Peter Friend, Martin Whiteley and Joanna Zawadzka
© Cambridgeshire Geological Society