TL 229026
Adjoins a Scheduled Ancient Monument
Boundary of chalk and overlying Tertiary deposits, with large solution pipes. Disused quarry, one face retained.
This geosite has not been visited in the recent past due to Lockdown and Covid considerations – the status reflects the situation in 2008. Once circumstances permit the site will assessed and relevant details provided here.

TL 349165
Former gravel pit. Nr Ware. Gravel & boulder clay from Pliestocene proto-Thames & Anglian glaciation.
This geosite has not been visited in the recent past due to Lockdown and Covid considerations – the status reflects the situation in 2008. Once circumstances permit the site will assessed and relevant details provided here.

tba

Location – Grid Reference TL 01650825

Car Parking – on Bullbeggars Lane which starts from the A4251 at the eastern edge of Berkhamsted and rises up the hill to Potten End. The site is on the right hand side as the road starts to level at the top of the hill and you can park on the roadside or at the crossroads just beyond the site.

Catering options – Martins’ Pond pub in Potten End, or numerous cafes, pubs and restaurants in Berkhamsted

The site is in an area of regenerated woodland, owned and managed by the National Trust as part of the Ashridge Estate. It is one of many pits which were dug during WWI to obtain road stone. The beds of sands and gravels were first described by Charles Gilbert in 1919 as mostly beach deposits of Pliocene age, but no fossils have been found so the age and origin have been subject to much debate.

This unique site was designated a Site of Special Scientific Interest (SSSI) in 1954. It was excavated again in 1978, the results of which are summarised in Hertfordshire Geology and Landscape (2010) book, edited by John Catt. It was excavated again in 2012 to take samples to determine the age by Cosmogemic Isotope Analysis, the full results of which are still to be published, but preliminary analysis indicate a date in line with Charles Gilberts original paper.

This video describes the history of the site, the 2012 excavation, the interpretation of the stratigraphy, the provisional results and ongoing geoconservation.

The vegetation continues to be cleared each year by members of HGS. The main face of the 2012 excavation has deteriorated, and will only be fully exposed again as and when further scientific analysis is undertaken with the agreement of the National Trust and Natural England .

See Geoconservation – HGS Active Sites for blog on HGS activity on the site.

References

Catt JA. 2010 – Hertfordshire Geology & Landscape. Hertfordshire Natural History

Society

Gilbert, CJ 1919. On the occurrence of extensive deposits of High-level sands

and gravels resting on the chalk at Little Heath near Berkhamsted. Quarterly

Journal of the Geological Society, London

Moffat, AJ & Catt, JA. 1983 A new excavation in Plio-Pleistocene Deposits at

Little Heath. Hertfordshire Natural History Society.

TL 145027
Access issue Industrial Site. Gravels (oldest 470-500ka) and clays from diversion of proto Thames during Anglian glaciation.
This geosite has not been visited in the recent past due to Lockdown and Covid considerations – the status reflects the situation in 2008. Once circumstances permit the site will assessed and relevant details provided here.

Location: TL 172299
Interglacial tufa (probably Hoxnian Interglacial 300-420ka).  Not exposed at the surface.

Oughtonhead Lane looking westwards

Oughtonhead Lane runs downhill westwards between overgrown banks, with a drop in elevation of some 10 metres along its length; it has been roughly paved in the past. It lies on the margin of a major glacio-fluvial channel running N-S through Hitchin, and the neighbouring field margins show patches of coarse flint-rich gravel.

This is an important tufa site thought to date from the Hoxnian interglacial, containing a rich assemblage of fossil land snails and small mammals which provide significant evidence for Quaternary environmental reconstruction and dating.  However, the tufa is not exposed at the surface.  It was originally discovered in a trench dug for laying a water pipe, and has more recently been investigated by means of test pits and augering.

Car Parking Roadside parking at top of Redhill Road, Hitchin.

Herts Geology & Landscape  p.164

Nearby Attractions
At its lower, westward end, the lane leads to Oughtonhead Common, a Local Nature Reserve containing the headwaters of the River Oughton (one of the few Hertfordshire chalk streams flowing northwards into the Ouse catchment) and various other springs.  It was designated for its variety of habitats – marsh, rough grazing, and drier chalk grassland.  On the far bank of the Oughton is a Nature Reserve managed by HMWT, containing fen woodland dominated by alder carr, but not open to the public.

A Walk at Water End…

Over several months in 2022 Liam Gallagher, an HGS member, visited Water End near Welham Green in Hertfordshire a number of times to gather information to update our records for this SSSI and to photograph the position of swallow holes at various times of the year under various hydrological conditions.

The geological aspects of the site are discussed in some detail here.

In addition a ‘self-guided walk’ around the site, with less geological ‘detail’ but with information on how to best access the whole of the site and how to enjoy the hydrogeology and geomorphology in a wider sense can be found here so you can enjoy the features of the Potterells Stream and Mimmshall Brook swallow holes ‘estate’.

Two videos support this walk:

and

TQ 071993
Proto-Thames deposit when flowing through Vale of St Albans (800-900ka) pre Anglian glaciation Includes volcanic pebbles from north Wales.
This geosite has not been visited in the recent past due to Lockdown and Covid considerations – the status reflects the situation in 2008. Once circumstances permit the site will assessed and relevant details provided here.