is a small disused chalk pit which lies 0.7km to the north of the village of Barkway and 4km south of Royston, near the top of the north-facing chalk scarp slopes. The site is of geological interest due to the chalk exposure, which was pushed over boulder clay by the Anglian Stage Glacier over 400,000 years ago. This geological feature was revealed by the excavation of chalk but is currently partially obscured by bramble (Rubus fruticosus agg.). Today, the pit is smothered by a vigorous crop of tall, ruderal vegetation predominantly comprised of common nettle (Urtica dioica). The edges of the pit are cloaked in mature scrub, which is gradually encroaching inwards. The site is presumed to have few visitors due to its location; however, it is known to have previously held interest for students and geological societies.

Take a virtual tour with Dr Haydon Bailey of the HGS, filmed for the 2020 Geologists’ Association virtual Festival of Geology (vFoG).

The Bourne Gutter is a unique winterbourne valley, where the river rarely rises and has in the past been called a woe stream because its flow coincided with major disasters in English history.

Take a virtual tour with Nick Pierpoint (HGS).

Puddingstone on roadside verge – Berkhamsted HP4 1HE

Perhaps the most enigmatic rock found in the county is Hertfordshire  Puddingstone, many fine examples can be seen in church buildings or as
free-standing boulders on the roadside. Several large blocks of Hertfordshire Puddingstone are accessible for inspection on the grass verge outside the house No. 13 Castle Hill link to video.  The largest block is partly sarsenstone (silcreted sandstone usually devoid of flint pebbles), though the sarsen part contained a line of dispersed pebbles. The importance of this specimen, demonstrating the close relationship between puddingstone and sarsen, has been recognised in designation of the group as a Hertfordshire RIGS site.

Puddingstone conglomerate

The puddingstone and sarsen (hyper link to Herts Geology HPS) originated by silicification of pebble beds or sand in either the Upnor Formation (late Palaeocene) or Reading Formation (early Eocene). As these deposits extended up the sub-Palaeogene erosion surface now exposed as the 6 dipslope of the Chilterns, the blocks had moved down the slope of Castle Hill from the plateau surface north of the Bourne Valley. The silcretes had probably formed within soil profiles developed in humid subtropical conditions on these formations in the Palaeogene, i.e. soon after their deposition.

Location Address – Castle Hill, Berkhamsted, HP4 1HE Hertfordshire

Location Grid Reference – SP 993 085

Car Parking – roadside parking possible

Catering – options include numerous cafes and pubs in central or canal side in Berkhamsted

Nearby Attraction – Berkhamsted Castle (HP4 1LJ) is a Norman motte-and-bailey castle in central Berkhamsted. The castle was built to obtain control of a key route between London and the Midlands during the Norman conquest of England in the 11th century. Can you find the dozen or so blocks of puddingstone incorporated in the castle walls?

Take a virtual tour with Nick Pierpoint (HGS) .

For more information take a look at:

• Hertfordshire Geology & Landscape p. 108 – 117
• East Herts Geology Club’s webpage on Puddingstone

Background
The site was excavated in 2012 under the leadership of John Catt, assisted by Clive Maton. It had the agreement of the owners, the National Trust, and the consent of Natural England, who have responsibility for SSSI’s.  A 10m wide face was exposed which allowed  a detailed view of the sedimentology and the collection of samples to use in the dating of the deposits by Cosmogemic Isotope Analysis. The excavation originally dug down to the chalk 9m below the surface, but the lowest 4m were back filled for safety.
For more information see Videos and Trails and Information Boards.

Geoconservation Activity
The site was left in good condition so that visitors could view the exposed section, but gradually the vegetation began to take over. Therefore, with the agreement of the National Trust and Natural England, in 2017 we held our first working party to clean up the site.  We have continued to do this on an annual basis.

2024

This year we chose the 17^th February for the Working Party, and again were fortunate with the weather. The previous week had been showery so forming some puddles, but we were blessed with another cloudy-bright day for our work.

A key focus this year was the Couch Grass which had not only spread further on the exposure but also across the bottom of the pit. Great work was done in both areas with the aim of removing a large portion of the roots. It will be back next year but hopefully at a reduced level.

Last year we pulled up a huge number of saplings, up to a foot high, across the whole site. That good work meant that we found very few to remove this year.

We were delighted that Joe, a Ranger from the Ashridge National Trust Management Team, was able to join us. He brought with him a hedge trimmer so was able to clear the vegetation from the righthand side of the pit very efficiently.

It allowed the us to focus more time on other areas, the entrance slope to the pit, the bottom of the pit, and at the top of the exposure. The later included removing the moss which was adding to the water erosion in the faces.

So a great result thanks to everyone’s hard work.

Heavy rain fell over the next two weeks. So, when three of us returned (in the rain) to do some more work, there was very sticky clay and a pond in the pit!

Our focus was to clean some of the key parts of the exposure ahead of a visit by Harrow & Hillingdon Geological Society planned for May. We also were able to clear large amounts of sand which had accumulated onto the exposure steps.

Another good morning’s work by the participants, who then had more work to do to clean tools and clothes!!

2023

The Working Party was arranged this year on 18^th February and managed to find cloudy-bright weather so ideal for a busy morning. We found that the good work done last year meant that our starting point was much improved. However the Couch Grass invading the main face is a problem which we tackled as best we could.

The main face is also getting a covering of moss and has started to slump in places. We have decided to do minimal work on the face, to protect the outcrop. If we were to clean the face each year the outcrop would be soon worn away. This way it will still be available for further research in the future.

The team again did a great job on clearing the vegetation on the site, and even managed to get to all the vegetation at the other end of the site from the face – a first!

2022

On 27th February a working party got back to Little Heath to clear the site after 24 months growth of vegetation. We were blessed with good weather, having moved the date from the previous weekend due to storm weather warnings!

John Catt was responsible for opening the exposure in 2012, and while he is no longer with us in person, it was lovely to have his spade to help with the work.

2021
No activity due to COVID-19

2020

2019

2018

2017

Front cover of the GA Magazine in June – Clive Maton describing the exposure at the end of the day’s work.

Inside article: ‘Geoconservation Little Heath, Near Berkhamsted, Hertfordshire’ by Nick Pierpoint. Read the full article on the GA’s website here.

Background
HGS became involved with Geoconservation of the site in early 2018 at the invitation of Hertfordshire Countryside Management Services team. A plan was developed, and in March 2019, with funding from the GA Curry Fund, a small excavator was brought onto the site to remove loose rubble from the chalk face and to excavate into the underlying Chalk Rock (Hitch Wood Hardground) section. All the material excavated from the site was piled up so that visiting geological parties and groups of local school children can collect fossils safely.

For more information, visit the RIGS page and scroll down to the section on Hill End Chalk Pit This includes a video visit to the site, the Information Board at the site, and a brief history of the site via a pdf download.

Geoconservation Activity
Initial clearing of vegetation and improved access was done after the excavation. However, over time the growth of vegetation and erosion of the exposure has required the need for working parties to maintain the site.

2023 July

A Working Party was arranged for 1^st July. The four year break due to Covid etc meant we had been kept away from the site, so we returned to find a large talus slope (about 3metres high) and significant growth of the vegetation.

Using picks and shovels about half the talus slope was removed, which was carried by buckets to the spoil heap, ready for any visitors to hunt for fossils. In parallel, a large amount of vegetation was removed to enable access to the site; clear the spoil heap; and make the exposure more visible

Plan is to return later in 2023 to remove the remainder of the talus slope. Also to contact the Hertfordshire Countryside Management Services to see if they can clear more vegetation around the exposure when they have their volunteers visit the site in the Autumn.

2019 June

We held our first conservation visit to the site during which a very large amount of overhanging vegetation was removed and the chalk face was returned to what it had been during the early 1980s

2019 March

The excavation was followed rapidly by Hertfordshire conservation volunteers visiting the site to clear a large amount of scrub vegetation and to build a new set of steps into the chalk pit. During this visit Jack Doyle was welcomed back on site to show the volunteers some of the important fossils which had been discovered there