1006982 – Grim’s Ditch: two sections in Portobello Wood, Holies Shaw and High Holies Wood Gap

Historic England listed monument: 1006982 – LiDAR Tile: SU57SE – Berkshire

GE Map

1006982 - Grim's Ditch: two sections in Portobello Wood, Holies Shaw and High Holies Wood Gap
1006982 – GE

OS Map

1006982 - Grim's Ditch: two sections in Portobello Wood, Holies Shaw and High Holies Wood Gap
1006982 – OS

1800 OS Map

1006982 - Grim's Ditch: two sections in Portobello Wood, Holies Shaw and High Holies Wood Gap
1006982 – 1800

LiDAR Map

1006982 - Grim's Ditch: two sections in Portobello Wood, Holies Shaw and High Holies Wood Gap
1006982 – Lidar
1006982 - Grim's Ditch: two sections in Portobello Wood, Holies Shaw and High Holies Wood Gap
1006982 – with prehistoric water levels
1006982 - Grim's Ditch: two sections in Portobello Wood, Holies Shaw and High Holies Wood Gap
1006982 – showing it’s TWO Dykes not one

SU 59382 79568

Length (m): 865

Orientation: W – E

Class Designation*:

Overall Width (m): 22

Ditch Width (m): 8

Bank Width (m): 6

Connectivity**: Paleochannel

Ditch Shape: ?

Volume (cu.m): 8,996 (@ 1.3 depth)

Man hours to complete: 29,986

Estimated Construction Date: Mesolithic

Number of Quarries*** (within 200m): 1

Number of Springs**** (within 200m): 0

Scheduled Monument Report:

None

Analysis:

This Dyke is not part of ‘Grim’s Ditch’ as shown on OS maps and HE publications. LiDAR clearly shows that this Dyke has no connections to the main Grim’s Ditch and was used to link a major quarry to the Thames. What has been overlooked is that this is in fact TWO Dykes that produce a Double Ditch Three bank section which then splits into to different Dykes entering the Thames at different points.

References:

https://historicengland.org.uk/listing/the-list/list-entry/1006982?section=official-list-entry

https://prehistoric-britain.co.uk/dyke-construction-hydrology-101

Further Reading

For information about British Prehistory, visit www.prehistoric-britain.co.uk for the most extensive archaeology blogs and investigations collection, including modern LiDAR reports.  This site also includes extracts and articles from the Robert John Langdon Trilogy about Britain in the Prehistoric period, including titles such as The Stonehenge Enigma, Dawn of the Lost Civilisation and the ultimate proof of Post Glacial Flooding and the landscape we see today. . (TSE DVD Introduction)

Robert John Langdon has also created a YouTube web channel with over 100 investigations and video documentaries to support his classic trilogy (Prehistoric Britain). He has also released a collection of strange coincidences that he calls ‘13 Things that Don’t Make Sense in History’ and his recent discovery of a lost Stone Avenue at Avebury in Wiltshire called ‘Silbury Avenue – the Lost Stone Avenue’. (TSE DVD Introduction)

Langdon has also produced a series of ‘shorts’, which are extracts from his main body of books:

The Ancient Mariners

Stonehenge Built 8300 BCE

Old Sarum

Prehistoric Rivers

Dykes ditches and Earthworks

Echoes of Atlantis

Homo Superior

For active discussions on the findings of the TRILOGY and recent LiDAR investigations that are published on our WEBSITE, you can join our and leave a message or join the debate on our Facebook Group.

For in-depth information about British Prehistory, we invite you to explore www.prehistoric-britain.co.uk, an extensive resource featuring archaeology blogs and investigations. This collection includes modern LiDAR reports that shed light on ancient landscapes. Additionally, you will find extracts and articles from the Robert John Langdon Trilogy, offering fascinating insights into Britain during the Prehistoric period. Some notable titles from the trilogy include “The Stonehenge Enigma,” “Dawn of the Lost Civilisation,” and groundbreaking evidence of Post Glacial Flooding and its impact on the landscape we see today.

Robert John Langdon has further enriched the exploration of Prehistoric Britain through his YouTube web channel, boasting over 100 investigations and video documentaries that complement his classic trilogy. In addition to his extensive work, Langdon has unveiled a compilation of intriguing coincidences titled “13 Things that Don’t Make Sense in History.” He has also brought to light his recent discovery of a forgotten Stone Avenue in Avebury, Wiltshire, aptly named ‘Silbury Avenue – the Lost Stone Avenue.’

For those who wish to actively engage in discussions about the findings from the TRILOGY and recent LiDAR investigations, we invite you to join our community. You can participate by leaving messages and joining debates on our dedicated Facebook Group. We encourage open dialogue and the exchange of ideas to foster a deeper understanding of Prehistoric Britain and its fascinating mysteries.

As you embark on your journey through British Prehistory, we hope these resources provide valuable insights and inspire further exploration of this captivating field of study.

NB. Recent investigations have indicated the location of hundreds of Quarries and pits built around Wansdyke and how the Dykes were used to transport the minerals transported in these Dykes – see the main site for details of blogs and books on this new discovery.