Essex is blessed with a surprising number of geological sites that are well worth visiting. Below is an alphabetical list of some of the more interesting ones.

These sites are publicly accessible at the time of publication (2022) or can be viewed from public footpaths. Ordnance Survey map references are given for each location. The inclusion of a site in the list does not necessarily imply a right of access. Please look after these areas and do your best not to disturb property or wildlife. Those sites for standing stones and boulders are just a selection from many others across Essex. 

Detailed descriptions of many sites of geological interest and importance are provided on the Essex Field Club website.

This list reproduced here by kind permission of Ian and Ros Mercer from their recently published book ‘Essex Rock’.

ALPHAMSTONE. Alphamstone Churchyard
(TL 878 354), Braintree district.
There are eleven sarsen stones here, eight in the churchyard, two by the road and one in the church. There are probably more buried in the ground locally. These are erratic boulders that have been gathered on this knoll in the distant past.

ALRESFORD. Cockaynes Wood Nature Reserve
(TM 056 218), Tendring District.
A former gravel pit with exposures of Wivenhoe Gravel, part of the bed of the ice-age River Thames half a million years ago. It was deposited just upstream of the point where the Thames joined a former course of the River Medway.

(TQ 921 968), Maldon district.
A cliff on the outer bend of the River Crouch near Burnham- on-Crouch is being eroded. Here, London Clay fossils have been found in the beach shingle including fossil bird bones and numerous shark teeth. There has been extensive collecting since the site was first discovered in the early 1970s and finding fossils here today requires good eyesight and a lot of patience. Transparent crystals of selenite (a variety of gypsum) can also occasionally be found.

ARKESDEN. Arkesden War Memorial
(TL 4821 3456), Uttlesford district.
The war memorial in St. Mary’s churchyard consists of a very large boulder of puddingstone 1.7 × 1.7 × 0.8 metres in size. This boulder was apparently brought here from somewhere on the Wood Hall estate, probably less than a mile to the south. In the bed of the stream (Wicken Water) by the road bridge in the centre of the village are a number of large erratic boulders.

AUDLEY END. Audley End House Septarian nodule
(TL 5217 3831), Uttlesford district.
On display in the Stable Block is a fine, large septarian nodule (165 × 115 × 30 cm in size) cut in half to reveal the internal calcite-lined cracks or ‘septa’. This nodule was no doubt collected locally and was part of the natural history collection acquired by the 4th Lord Braybrooke in the nineteenth century.

BEAUMONT. Beaumont Quay Limekiln
(TM 190 240), Tendring district.
The circular brick limekiln at Beaumont Quay is the only complete limekiln surviving in Essex, dating from around 1869–70. It had fallen into disuse by the early 1920s. Limekilns were often built in harbours and wharfs where chalk and coal for the kiln could be brought in by sea. Owned by Essex County Council and publicly accessible.

BLACK NOTLEY. Friar’s Farm Boundary Stone
(TL 7427 1970), Braintree District.
A sarsen stone that is described by English Heritage as a rare survival of an inscribed and dated boundary stone dating back to the seventeenth century. Sarsen stones used for specific purposes in historical times are rare and this is a splendid example.

BRENTWOOD. Thorndon Country Park North
(TQ 604 915), Brentwood district.
Thorndon Country Park has some interesting landforms which enable the geology to be appreciated. To the south a spread of glacial gravel is dissected by several streams, which have cut through the Claygate Beds exposing the underlying London Clay. Glacial gravel is well exposed in a gravel cliff at the east end of the park with a signboard explaining the geology. A geological ‘Pebble Walk’ trail guide is available.

CHAFFORD HUNDRED. Chafford Gorges Nature Park
(TQ 599 793), Thurrock district.
Chafford Gorges Nature Park is the finest area for geology in south Essex. Spectacular Chalk cliffs can be seen, a legacy of quarrying for the Portland Cement industry. The Chalk is overlain by Thanet Sand and gravels from former routes of the Thames during the ice age. There are also several fine sarsen stones around the rim of Grays Gorge. The park consists of seven geological sites (Grays Gorge, Lion Gorge, Lion Pit Tramway Cutting SSSI, Millwood Sand Cliff, Sandmartin Cliff, Warren Gorge and Wouldham Cliff ), looked after by Essex Wildlife Trust. Lion Pit Tramway Cutting SSSI is one of the most important of the county’s SSSIs, yielding evidence of human occupation on the banks of the Thames 200,000 years ago. The visitor centre has views overlooking Warren Gorge. A geological trail guide is available.

CHELMSFORD. Chelmsford Museum Puddingstone
(TL 7025 0558), Chelmsford district.
Large boulder of puddingstone, with a signboard to tell its story, in the ornamental garden near the entrance to Chelmsford City Museum and café in Oaklands Park.

COLCHESTER. Lion Walk United Reformed Church
(TL 9971 2506), Colchester district.
The top of the church spire fell into the street during the 1884 earthquake and the Illustrated London News at the time published an impressive engraving of the occurrence with people fleeing from the scene. The church has since been demolished but the tower (with its rebuilt spire-top) was spared and it remains as a prominent landmark in the town shopping centre. A plaque commemorates the event.

EAST MERSEA. Cudmore Grove Cliffs and Foreshore
(TM 068 146), Colchester district.
The cliffs at Cudmore Grove Country Park provide superb exposures of gravels laid down by the ancient River Blackwater during a glacial period 300,000 years ago. Riverbed sediments at beach level sometimes yield fossils, including mammal bones, that indicate that they were deposited during an interglacial period. Also exposed on the foreshore are deposits from a more recent interglacial period, the Ipswichian interglacial (120,000 years old), and known as the ‘hippo site’ due to the presence of hippopotamus bones.

EPPING. Wintry Wood Brick Pit
(TL 469 035), Epping Forest district.
Disused brick pit in Wintry Wood adjacent to Brickfield Business Centre (formerly Wintry Park Brick & Tile Works). Steep banks have Anglian glacial till (‘chalky boulder clay’) visible in tree roots. This pit is a rare example in Essex where direct evidence of the ice sheet can be seen. The pit is in the Lower Forest (part of Epping Forest). Layby for parking nearby.

EPPING FOREST. High Beach Viewpoint
(TQ 411 981), Epping Forest district.
The high ground around the King’s Oak inn is capped with High-Level Pebble Gravel (Stanmore Gravel), which is likely to have been deposited by a tributary flowing north from the area of Kent, to join the ancestral Thames across north Essex and Suffolk (gravels of similar composition occur at the top of Shooters Hill on the south side of the Thames). Well-rounded flint pebbles from this gravel are revealed in the many footpaths. Beneath this gravel is Bagshot Sand from a delta that spread across Essex 50 million years ago. This fine yellow sand is visible on the steeply sloping paths to the north-west of the inn.

FINCHINGFIELD. Finchingfield Boulder
(TL 6849 3290), Braintree district.
A splendid boulder of basalt volcanic rock 85 centimetres long lies by the roadside on the left-hand side a few metres from the village green on the road north out of the village. This boulder was probably transported south from Northumberland or Scotland by the Anglian ice sheet. Large erratic boulders of basalt are very rare in Essex.

FINGRINGHOE. Fingringhoe Wick Nature Reserve
(TM 045 195), Colchester district.
Essex Wildlife Trust nature reserve. Fingringhoe Wick was a working gravel quarry until 1959. Visible in many places are mounds and banks of glacial sand and gravel (known locally as Upper St Osyth Gravel) which was deposited some 450,000 years ago by torrents of meltwater issuing from the Anglian ice sheet, the edge of which was then situated only 12 kilometres west of here. The gravel therefore provides evidence of an exceptionally cold period in the ice age. A permanent vertical section through the gravel exists in the centre of the reserve.

GESTINGTHORPE. Nether Hall Farm Sarsen Stones
(TL 809 393), Braintree district.
Nine sarsen stones on roadside by farm entrance, the largest 2.4 metres long. The area around Gestingthorpe is notable for the large number of sarsen stones that can be found at road junctions and by farm gates, all recovered from local fields by farm workers.

(TQ 939 872), Rochford district.
Low cliffs of yellowish brickearth (loess) can be seen adjacent to footpaths in this pit in a wildlife reserve. Loess is a fine silt deposited during huge dust-storms carried from the cold, dry land around the edge of an ice sheet. It was possibly deposited during the coldest part of the most recent glaciation of Britain, by about 20,000 years ago.

HADLEIGH. Hadleigh Castle Landslip
(TQ 810 860), Castle Point district.
The most impressive London Clay landslip in Essex. The severe effects on the castle are obvious. Further, larger slipping in the field and footpath to the east, towards Leigh-on-Sea, are seen from the eastern edge of the castle.

HADLEIGH. Hadleigh Country Park
(TQ 799 868), Castle Point district.
Undulating landscape of London Clay, overlain by Claygate Beds and rounded hills of Bagshot Sand. An exposure in the Bagshot Sand delta was created in one hill in 2016, close to the site of British Geological Survey’s 1973 Hadleigh borehole. The small cliff of yellow sand and a signboard are on the geological trail around the park, with a trail guide available at The Hub. Here also, in the topsoil, fragments of Kentish chert looking like small lumps of toffee tell of the former course of the ancient River Medway across this area. Fine views across meanders in local rivers on the floodplain and across the Thames to Kent and the Chalk of the North Downs.

HARWICH. Harwich Foreshore SSSI
(TM 263 320), Tendring district.
This locality has the best exposure of the Harwich Stone Band, the most distinctive of the cementstone bands in the Harwich Formation at the base of the London Clay. It contains volcanic ash from explosive volcanic eruptions in Greenland as the North Atlantic started opening out during Eocene times, some 55 million years ago. The stone band makes this part of the coast the only naturally occurring rocky shore along the entire distance between Norfolk and Kent and may be one reason for the existence of the Harwich peninsula. The foreshore is also of prime importance for London Clay fossils, particularly for fossil fruits and seeds from the Eocene rainforest. Also found are fossil shark teeth amongst the beach shingle.

(TQ 5200 9222), Havering London Borough (Essex vice-county).
A boulder of dolerite from the Whin Sill lies on the terrace of the Essex Wildlife Trust visitor centre, with a signboard on the other side of the wall. The boulder was transported within the Anglian ice sheet from the north of England. The Whin Sill is a feature across the landscape upon which the Hadrian’s Wall was built. This boulder was evidently caught in the diverted Thames river flowing around the edge of the melting ice sheet to the south of here, perhaps in an ice floe, and came to rest in the gravel riverbed. It was found in a gravel pit at Marks Gate 450,000 years later and kindly donated by Brett Aggregates. From this area of the park there is a fine view of the ‘staircase’ of lower Thames terraces and across to the Chalk of the North Downs of Kent.

INGATESTONE. Ingatestone Boulders
(TQ 6511 9967 and TQ 6511 9959), Brentwood district.
Two well-known sarsen stones protect the junction of the High Street and Fryerning Lane, the larger one a metre tall. Another stone is situated a short distance away by the south door of St Edmund and St Mary Parish Church which has one of the earliest brick-built towers in Essex, plus a north wall of ferricrete and Roman brick.

LANGDON HILLS. Langdon Hills Country Park
(TQ 683 866), Basildon district.
London Clay and Claygate Beds with Bagshot Sand capping the highest ground. This in turn is capped by High-Level Gravel (Stanmore Gravel), an ancient bed of a river flowing from the south. There are sunken lanes up the steep hill to the west where the old road cuts into the Bagshot Sand layer. Disused sand and gravel pits are seen in the woods and small toffee-like fragments of Kentish chert are common amongst the flint pebbles in the footpaths. Spectacular views across the Land of the Fanns (Bulphan Fen) and the Thames Estuary and most of London. Part of the site is in Thurrock District.

LEXDEN. Lexden Springs Nature Reserve
(TL 973 253), Colchester district.
In Spring Lane, off Lexden Road, is a patch of ancient meadowland which is generally rich in wildflowers. Here a natural spring issues from the junction of the Kesgrave Sands and Gravels and the underlying London Clay.

LITTLE WALTHAM. Channels Sarsen and Puddingstone (TL 7238 1118), Chelmsford District.
By the entrance to the Channels venue is a large boulder of puddingstone on a mound of grass by the roadside. It is one of the largest puddingstone boulders in Essex, measuring more than 2 by 1 metres. Close by are boulders of sarsen, including one large piece that has a trace fossil trackway along its front surface, plus the root holes left from plants that grew in the sandy soil that became transformed into this tough sarsen quartzite. These were found in the former Channels gravel pit.

LITTLE WALTHAM. Channels Glacial Till Wall
(TL 7216 1100), Chelmsford District.
Within a new housing development, a public footpath offers a view of the only easily seen exposure, anywhere in Essex, of glacial till, the Chalky Boulder Clay left by the Anglian ice sheet that covered the Thames gravel in this area. At the time of writing (2022) a signboard is proposed to be set next to this remaining quarry face of the former gravel workings.

(TL 907 035), Maldon district.
The foreshore on the east bank of Lawling Creek, north of Maylandsea, has yielded large numbers of London Clay fossils, particularly crustacean remains such as lobsters. The SSSI citation states that this section of ‘soft rock’ coastline is of national geological importance. The site demonstrates the maximum extent of the London Clay sea, with fossils indicating a deep-water fish fauna.

MISTLEY. High Street Cobble Wall
(TM 117 318), Tendring district.
On the south side of Mistley High Street, just east of the post office, is a brick wall with a panel composed entirely of rounded cobbles. Here can be seen numerous ‘exotic’ rock types such as granite, dolerite and gneiss and the distinctive Norwegian rock known as ‘rhomb porphyry’, of which there are at least eight examples here. The high number of the Scandinavian rocks in such a small section of wall is extremely unusual and, situated opposite the Baltic Quay on the adjacent Stour, and ‘Ballast Hill’ within the river, it is more than likely that these cobbles are of ships’ ballast from maritime trading 150 to 200 years ago. The wall is a geological museum of delight.

MISTLEY HEATH. Furze Hill Gravel Pit
(TM 122 309), Tendring district.
The disused gravel pit at Furze Hill, adjacent to the long-distance Essex Way footpath, has exposures of Waldringfield Gravel. This is the oldest deposit in Essex from the former River Thames, at least 650,000 years old. Gravel seen in small excavations along the paths and in roots of fallen trees contains ‘exotic’ rocks that have been carried some distance by the Thames, such as small pebbles of pure white vein quartz possibly from North Wales and rare black-and-white tourmaline quartz pebbles from Cornwall, as well as numerous flints of all colours.

NAVESTOCK. Millennium Stone
(TQ 5460 9613), Brentwood district.
A giant boulder of ferricrete sits on a concrete plinth by the road. Excavated from a nearby field, it is 2.1 by 1.5 metres in size and was placed here in 2000 to mark the Millennium. It is mistakenly inscribed as being a ‘puddingstone’.

NEWPORT. The Leper Stone
(TL 5199 3496), Uttlesford district.
A large coarse-grained sarsen stone 1.7 by 1.2 metres in size known as the Leper Stone sits upright on the grass road verge at the north entrance to the village. This is the best-known erratic boulder in north Essex. Adjacent to this is a wall constructed largely of blocks of clunch, a hard variety of chalk formerly used for building.

PURFLEET. Purfleet Submerged Forest
(TQ 5445 7871), Thurrock district.
Part of a submerged forest, between 5,000 and 6,000 years old, consisting of fallen tree trunks and roots, with some rare leaves, is exposed on the Thames foreshore, at low tide only. This site and other submerged forests along the Thames (e.g. at nearby Rainham) have been studied for their importance in the interpretation of sea-level changes since the end of glacial conditions 11,700 years ago.

SAFFRON WALDEN. The Gibson Boulders
(TL 5369 3817), Uttlesford district.
At the junction of Gibson Gardens and Margaret Way is a mound of grass and trees containing at least 25 glacial erratic boulders of varying sizes. At least ten different rock types are seen here. The largest is a slab of colourful puddingstone 1.2 metres long. The site also has great historical interest: the Gibson Gardens estate was built on land that was formerly the gardens owned by George Stacey Gibson (1818–1883), naturalist, who had a great interest in geology. An 1877 map shows this mound to be the site of his summer house and it seems certain that he accumulated these boulders in his garden. They were almost certainly gathered from the farmland that he owned in the vicinity.

ST OSYTH. Colne Point Shingle Spit
(TM 109 123), Tendring district.
Colne Point is the best example in Essex of a shingle spit. The spit is 4 kilometres long and is nearly all that remains of a much larger area that existed in the nineteenth century but has now mostly been developed by the seaside holiday industry. It is of great interest for studying the movement of shingle and the development of shingle structures. It is an Essex Wildlife Trust reserve. Day permits to visit are available from the Trust.

ST OSYTH. St Osyth Priory Gatehouse
(TM 121 157), Tendring district.
Erected in 1481, the battlemented gatehouse of St Osyth Priory is one of the finest examples in Britain of the use of flint ‘flushwork’ – the name given to the technique of setting ‘knapped’ flints (skilfully worked to produce a flat face) into a wall, often in intricate patterns alongside another stone

ST OSYTH. St Osyth Priory Gatehouse
(TM 121 157), Tendring district.
Erected in 1481, the battlemented gatehouse of St Osyth Priory is one of the finest examples in Britain of the use of flint ‘flushwork’ – the name given to the technique of setting ‘knapped’ flints (skilfully worked to produce a flat face) into a wall, often in intricate patterns alongside another stone such as limestone. St Osyth’s Priory is privately owned and no longer open to the public but the gatehouse can be viewed from the green open space between the gatehouse and the road where there is also car parking. The adjacent Priory boundary wall along to the village crossroads is largely faced with excellent examples of buff-coloured cementstone, probably from Harwich, together with black flints.

SOUTH OCKENDON. Davy Down Sarsen Stone
(TQ 592 800), Thurrock district.
Davy Down Riverside Park forms part of the Mar Dyke Valley, a delightful valley with steep, wooded sides that can be seen from the M25 motorway. The valley runs along the northern side of the Purfleet ridge between Purfleet and Grays. Also of interest is the former waterworks containing old pumping engines, in front of which is a remarkable sarsen stone – one of the finest examples in Essex. The sarsen is 1.6 metres square and has fine mammillated surfaces.

STANWAY. Church Lane Gravel Cliff
(TL 945 238), Colchester District.
The disused gravel pits south of Church Lane have mostly been infilled and much of the land is now occupied by housing. However, a steep cliff of Thames gravel with glacial outwash gravel above is preserved south of Church Lane just west of the new Stanway Western Bypass. This cliff is a rare survival.

TOLLESBURY. Woodrolfe Creek Saltmarsh
(TL 969 105), Maldon district.
The best and safest place to view saltmarsh in Essex, with its creeks and tidal flats, is at Tollesbury. Here the marsh is criss-crossed by paths to enable boat owners to reach their vessels. This shows where new geological layers are being created.

UGLEY GREEN. Ugley Green Puddingstone
(TL 524 271), Uttlesford district.
Beside the green, next to the village pump, is a fine, rounded and colourful boulder of Hertfordshire puddingstone 1.2 metres long.

(TM 266 235), Tendring district.
The finest geological site in Essex. Classic cliff section in London Clay, Red Crag, brickearth and Thames Gravel (Cooks Green Gravel). Volcanic ash bands and faults in London Clay. Classic rotational landslips. Diverse fauna of fossils from Red Crag and London Clay. Site of international importance. A geology trail guide is available from GeoEssex and Essex Wildlife Trust. The tower contains a showcase of geological and archaeological finds and a GeoEssex display of beach finds is seen in a showcase within the EWT Centre nearby. The all-round views – for a small charge – of the land and seascapes from the top of the tower are truly stunning.

WENDENS AMBO. Wenden Place Boundary Wall
(TL 512 363), Uttlesford district.
On the bend of the main road opposite the church is a high, ancient wall, which is remarkable for the variety of local rocks used in its construction, including many large boulders. The largest is a puddingstone 1.4 metres long. The wall is a Grade 2-listed building.

WHITE NOTLEY. White Notley Puddingstone
(TL 7880 1772), Braintree district.
By a cottage gate is a fine, colourful boulder of Hertfordshire puddingstone 1.1 metres long. This boulder has been referred to in articles and books more often than any other puddingstone in Essex.

WRABNESS. Wrabness London Clay Cliffs and Foreshore (TM 172 323), Tendring district.
The London Clay cliffs on the River Stour at Wrabness are the highest vertical cliffs in Essex and consist of the upper part of the Eocene Harwich Formation and the lower few metres of the Walton Member of the London Clay. They provide the best onshore exposure of the Harwich Formation. These cliffs are of particular interest because they contain a complete sequence of bands of volcanic ash, which originated from volcanoes in Greenland 55 million years ago. These ash bands are present above the Harwich Stone Band which is very well seen along the top of the beach. The site has also yielded an important fossil flora preserved in concretions, as well as mammal bones and worked flints from interglacial deposits further along the shore.