Broom Pit, west of Orford, preserves unusually shelly Pliocene Coralline Crag. Its cross-bedded sands, bryozoans and contrasting weathered layers record an ancient shallow sea and later changes in fossil preservation. This woodland pit is private, so permission and an agreed approach are essential before a visit.
FIND FREQUENCY: ♦♦♦♦♦ – Shelly material is documented; collecting opportunities depend on an authorised visit and current exposure.
CHILDREN: ♦♦ – Follow the organiser’s age and safety requirements; this is not an open family collecting site.
ACCESS: ♦♦♦ – Prior landowner permission is required; agree parking and the woodland approach.
TYPE: – Private inland Coralline Crag pit.
DIRECTIONS
♦ Arrange permission before visiting. Broom Pit lies west of Orford in the wooded area known as The Broom, north-west of Richmond Farm. The original approach runs south-west from Orford, then north-west beside Richmond Farm towards the woodland. Meet and park only where the landowner or organised-visit leader directs, then use the agreed woodland track to the pit. The old guide described a walk of about half a kilometre from its woodland-edge parking place; this is not an invitation to park on farm or woodland tracks without agreement. Locality reference: TM 4063 4995, approximately 52.09568°N, 1.51169°E.
FOSSIL HUNTING
Broom is unusual among Coralline Crag pits because substantial shelly material survives below the weathered upper part of the succession. Both bivalves and gastropods occur, together with bryozoans; the more silty low levels preserve large, often complete shells. Historical collections are extensive, but they can mix the lower Sudbourne and upper Ramsholt members, so their entire species list should not be assigned to a single bed.
The published section specifically records Astarte and a large carditid historically named Venericardia aculeata scaldensis. That carditid name is quoted in its historical usage. The revised bryozoan Pentapora pertusa has museum material from Broom Pit. For an authorised visit, examine permitted loose material on the floor well away from unstable faces. Do not dig into the face. Any floor sampling must be specifically agreed: the permission given to a scientific work party does not grant it to later visitors.
A chronological record of geological research and significant discoveries at Broom Pit (Broom Hill, Gedgrave).
1863–1871 – Classic shell collection documented
Prestwich’s 1871 account listed 65 mollusc species collected in 1863 and described roughly 6.7 m of section.
1898 – Buried base investigated
Harmer listed Broom Hill as locality 11 and investigated the deeper contact beneath the pit.
1928 – Exposures largely lost
Boswell reported that less than a metre remained exposed after slips and talus obscured the former collecting section.
1999 – Member relationships reassessed
The GCR account documented the reopened deep section and distinguished the main Sudbourne sands from the probable Ramsholt beds below.
2010 – Bryozoan revision includes Broom specimens
A systematic revision of Pentapora included Natural History Museum specimens from Broom Pit and retained Pentapora pertusa as a fossil species.
2023 – Permission-based conservation work
GeoSuffolk and Coast & Heaths volunteers cleared an exposure and investigated a floor trench with the landowner’s permission; the trench was backfilled afterwards.
References
Balson 1999: Broom Hill, GCR volume 15, pp. 275–277
BGS district explanation: Coralline Crag members
Taylor and Milne: Coralline Crag bryozoans
Lombardi and colleagues 2010: systematics of Pentapora
GeoSuffolk Times 57: March 2023 authorised work party
GEOLOGY
Broom Pit exposes the Pliocene Coralline Crag, an older marine deposit than the Red Crag of several other Suffolk pits. Much of the documented face belongs to the Sudbourne Member, where carbonate-rich sand is built largely from shell and bryozoan debris. Its inclined layers record underwater sandwaves migrating south-west. Occasional thin mud drapes show interruptions in sand movement, while pieces of eroded mud incorporated into the sand record renewed stronger currents.
One of the clearest contrasts in the section developed after deposition. The upper sediment described in the published account was dark orange-brown and leached of aragonite, the carbonate mineral forming many molluscan shells. Beneath it, pale grey sand retained abundant aragonitic shell debris. Dissolution also extended downwards in pipes, so the boundary between well-preserved and leached sediment is a weathering feature, rather than the original boundary between two marine environments. Cross-bedding continues below the weathered zone: good shell preservation alone does not identify the Ramsholt Member.
Near the bottom of the documented face, distinctly siltier sediment with large complete molluscs was considered probably Ramsholt Member, although its exact contact remained uncertain. Historical fossil collections may consequently include material from both the lower Sudbourne and upper Ramsholt succession. The older assignment of the whole section to Ramsholt-equivalent beds was revised after its cross-bedding was recognised. London Clay was reported farther below the historical pit floor and should not be imagined as an exposed bed at the base of the present face.
Detailed stratigraphy and geological evidence at Broom Pit (Broom Hill, Gedgrave).
CRAG GROUP
The site exposes the Coralline Crag succession; the strata are older than the Red Crag at Alderton and Neutral Farm.
Coralline Crag Formation
The historical GCR description recorded a pit about 9 m deep with a western face roughly 40 m across. These are survey-era dimensions; exposure changes with vegetation, weathering and management.
Sudbourne Member
Cross-bedded carbonate-rich sand occupies much of the described section. South-west-dipping foresets indicate sandwave migration. The presence of cross-bedding below the weathered zone shows that the shelly lower sands cannot all be assigned to the Ramsholt Member merely because their preservation is good.
Upper leached zone
The upper 4.7 m in the published description was dark orange-brown and had lost aragonitic shell material. Solution pipes extended a metre or more below the top. This is a later weathering division, not a formally named member or a synchronous sedimentary boundary.
Lower unleached cross-bedded sands
Fresh sediment below the leached zone was pale grey and rich in aragonitic shell debris. Weak cementation and weathering made some cross-bedding conspicuous. Occasional mud drapes and eroded mud clasts document pauses followed by stronger currents.
Ramsholt Member — probable basal exposure
Near the bottom of the documented face, the sediment became distinctly siltier and included large complete molluscs. Balson regarded attribution to the Ramsholt Member as probable, rather than proving a sharply measured contact. The exact contact remains uncertain.
Historical deeper succession
Harmer’s 1898 investigation placed the London Clay contact a further 6.7 m below the pit floor as it then stood. This does not establish a visible basal gravel or London Clay exposure in the modern pit.
Prestwich’s historical zones
In 1871 Prestwich described 7 ft of zone e over 15 ft of zone d, totalling 22 ft (about 6.7 m). This historical scheme treated the section as the equivalent of Ramsholt beds; later recognition of cross-bedding assigns much of it to the Sudbourne Member. The early extensive fossil collections may mix the lower Sudbourne and upper Ramsholt faunas.
References
UK Fossils: Broom Pit, original route and last-inspected year
Balson 1999: Broom Hill, GCR volume 15, pp. 275–277
BGS district explanation: Coralline Crag members
Taylor and Milne: Coralline Crag bryozoans
Lombardi and colleagues 2010: systematics of Pentapora
GeoSuffolk Times 57: March 2023 authorised work party
SAFETY
The old quarry has high, locally overhanging faces. Loose sand, shells and blocks can fall suddenly, particularly after wet or frosty weather. Stay well beyond the base of unstable faces and away from the rim; do not tunnel, undercut or climb. Woodland undergrowth can conceal hollows and obstructions. Join an authorised organised visit if you are unfamiliar with the site.
EQUIPMENT
Bring sturdy footwear, a hand lens, notebook or camera and plenty of small padded specimen boxes. A trowel or small sieve is appropriate only for work expressly agreed for that visit. Do not bring a spade expecting unrestricted pit-floor excavation.
CLEANING AND TREATING
Keep each permitted specimen with its locality and bed information. Support fragile shells or bryozoans in tissue inside a rigid box. Allow damp specimens to dry slowly away from heat, then begin with a soft brush. Do not force compacted sand from delicate shell edges. Avoid acids, bleach and varnish. If an exceptionally fragile specimen needs consolidation, seek advice before using a reversible conservation adhesive such as Paraloid B-72; routine coating is unnecessary.
IDENTIFY YOUR FINDS
Need help identifying a fossil? Share clear photos, where you found it and its size with the community.
FURTHER READING
Deposits: Pliocene bryozoans in the Suffolk Coralline Crag
Broom Hill: Geological Conservation Review account
GeoSuffolk: conservation work at Broom Pit in 2023
ACCESS RIGHTS
This is private land. Arrange permission from the landowner or operator before entering the pit, including agreement on the approach, parking and any collecting. A public path nearby does not give permission to enter the excavation. Follow the visit organiser’s conditions; permission for a visit is not automatically permission to dig, clear vegetation or take bulk samples. Broom Pit’s private ownership and permission-based visits are explicitly documented by GeoSuffolk. Its appearance in scientific literature is not evidence of public access.
It is important to follow our ‘Code of Conduct’ when collecting fossils or visiting any site. Please also read our ‘Terms and Conditions’.
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