Orwell Clunch Pit now an LGS

Orwell Clunch Pit was designated a Local Geological Site in October 2021. The pit is also an SSSI for its chalk grassland flora. It is owned and managed by the Parish Council and is an attractive local ‘greenspace’ with wonderful views across the Rhee...
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Two new LGS at Burwell

Two new Local Geological Sites designated at Burwell We are very pleased to announce that our latest proposal for designation as  Local Geological Sites (LGS) were recently (October 2020) approved by the County Wildlife and Geological Sites Panel. The two sites, 400m...
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The sea in the Fens

The Fens have been inundated by the sea on various occasions as shown by the marine silts and clays that can be found over large areas, even in the southern fenland of Cambridgeshire. The complex history of freshwater marshes changing to salt marshes and back again,...
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New Local Geological Site: The Great Fen

New Local Geological Site The Great Fen: Holme Fen and Whittlesea Mere LGS We are very pleased to announce that our latest proposal for designation as a Local Geological Site (LGS) was recently (Feb 2020) approved by the County Wildlife and Geological Sites Panel. The...
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Ice Age display, Sedgwick Museum

A superb mammoth tusk is now part of the Sedgwick Museum’s new Ice Age display. Sir John Franklin’s ill-fated expedition to the North-West Passage has often been in the news ever since he left England on the 19th May, 1845 never to return. Successive searches...
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Protecting the landscape heritage of the fens

The fenland has always been a land of mystery. This is particularly true when trying to unravel the complex history of dynamic changes in the landscape, which are directly linked to both sea level and climate. Thanks to an increase in research in recent years, much...
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Lime kilns at Isleham

Built around 1860, these listed buildings are the remains of a thriving clunch quarrying industry in this Fen Edge village. Three of the kilns are preserved, with the fire hearths visible inside. The clunch rubble was loaded in through the circular openings at the top...
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The economic geology of Burwell

Download our leaflet on the Aspects of Geological Interest in Burwell. Burwell is a “Fen Edge” village which lies to the North East of Cambridge. It has a long history, some of which was dependent on the geology of the underlying rock. It has evidence of...
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Nine Wells LGS display at the Cambridge Museum

A display about the Nine Wells Local Geological Site has been featured as part of an exhibition at the Cambridge Museum on the importance of Hobson’s Conduit.The exhibition runs from 26th September to 22nd October 2017 and can be seen in the tea rom at the...
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Nine Wells designated as Local Geological Site

Nine Wells Local Nature Reserve is now (February 2017) a Local Geological Site. This designation highlights its geological value for scientific, educational, historical and/or aesthetic reasons. As well as being the source of Hobson’s Conduit, the chalk springs at...
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Promoting interest in the geology of Cambridgeshire, the UK and worldwide

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Monthly Talks

The CGS are currently preparing a programme of 10 talks running from September 2021 to June 2022. These talks are held on the second Monday of every month and are at 7.30 pm unless specified otherwise. Due to the current COVID restrictions these talks are being held on ZOOM and are free – although donations are welcome! Talks are recorded but the recorded version is only available to members as part of their membership benefits.

The full programme is available on our EVENTS page. The next lecture will be held on Monday 13th September at 7.30pm.


Monday 14th February 2022 7.30pm

(by ZOOM – please register by contacting us)

The Geology of the Chilterns and the impact of HS2

Dr. Haydon Bailey, University of Birmingham and Geological Adviser, The Chiltern Society

The Chiltern Hills are underlain by Chalk, predominantly what was traditionally called the Middle Chalk (now the lower part of the White Chalk Group) capped by the Top Rock – Chalk Rock complex. It is this series of chalk hardgrounds which effectively forms the spine of the Chiltern Escarpment. The Chalk dips gently into the London Basin, and the overlying basal Tertiary succession provides minor outliers around this northern rim of the basin. The other major geological event we have to recognise in this area is the re-routing of the Proto-Thames River during and following the Anglian glaciation, some 450,000 years ago. This created the landscape we currently see in much of the southern parts of the Chilterns. The planned route of the HS2 fast rail link passes straight across the Chilterns Area of Outstanding Natural Beauty (AONB) and the geology underlying this region needs to be considered carefully whilst tunnelling is being carried out; some concerns will be raised regarding the tunnelling proposed under the Chilterns, the geology it will encounter and it’s impact on the surrounding AONB.

Recent Events


Field Trip Report – Burwell Local Geological Sites

The society organises occasional field trips to view important geological sites within the county and hopefully further afield in post pandemic times. These trips are primarily for our members.

In early summer 2021 we had a popular visit to the Burwell Local Geological Sites and are scheduling some others to East Pit, Cherry Hinton, a walk along the Fen Edge from Swaffham Bulbeck to Reach, a visit to Nine Wells chalk spring and a tour of the building stones of Cambridge city center. These are primarily for the benefit of members: any member wishing to participate should contact us.

A write up for this trip may be found here.


Two New Walk Guides published on the Fen Edge Trail

Earith to Needingworth and Sutton to Haddenham

Earith to Needingworth: Partly following the River Great Ouse, the walk takes you through a gentle landscape that does not resemble the large, ’Ice Age’, braided river that formed the lower part of the valley as it reached the fenland basin. Extensive research by Cambridge Archaeological Unit has revealed many significant cultural sites showing that people adapted to changing water levels over the last few thousand years, in a dynamic delta-like landscape. The furthest extent of the sea incursion c.3,400 years ago, during the Bronze Age, saw marine conditions extend to just south of Earith and waterways were possibly tidal much further inland.

Sutton to Haddenham: This walk passes over North Hill, the highest hill in the Cambridgeshire Fens, in the south west of the Isle of Ely. Prior to the major draining of the Fens in the 17th century, the Isle was surrounded by freshwater marshes and meres. This walk follows ancient droves and ways, alongside the Catchwater Drain, around the edge of the Isle linking these historic villages that sit on key promontories where, once, our ancestors sat and looked out across marshes or, sometimes, even sea.



Our December 2021 newsletter is now available to members.

Our previous newsletters are available to everyone (download below). They have plenty of ideas for some virtual geology!

CGS Newsletter August 21

CGS Newsletter April 2021

CGS Newsletter December 2020

CGS Newsletter July 2020

CGS Newsletter April 2020

Email updates

Sign up for our email updates to hear about future talks, events and news of our projects.

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Cambridgeshire Landscapes

Cambridgeshire has a fascinating landscape and an interesting geology. See our Landscapes page for more details and download the excellent leaflet ‘The Mapping of Landscapes, Geology and Soils of Bedfordshire and Cambridgeshire’ by Timothy Farewell, Peter Friend, Martin Whiteley and Joanna Zawadzk.


Our talks and other events

meet us

Local sites

Chalk cliff East Pit



Hippopotamous, Sedgwick useum


Local landscapes

The Fens




The Fen Edge Trail

Landscape Heritage

Mare Fen, Swavesey



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