Shoreham-by-Sea: Geology 

The low lying town of Shoreham-by-Sea is built on level land almost entirely below 7.7 metres (25 feet) above sea level (Ordnance Datum, 3.27 metres* above Chart Datum).  (for Shoreham Harbour * to be double checked)





MicrasterMicraster decipiens

See "The Chalk of Sussex and Kent" by Rory N. Mortimore
Beeding Quarry

Revised: Coniacian (88 million years ago) from Shoreham Cement Works. The flints on the beach are younger Santonian rocks. The Shoreham downs is a zone indicated by Micraster  fossils. The Coniacian is a stage of the Late Cretaceous Epoch. It spans the time between 89.3 ± 1 Ma and 85.8 ± 0.7 Ma (million years ago).

85 million years ago, Cretaceous Period (144 - 66.4 million years ago): Sussex is covered by a warm sea inhabited by ammonites, Micraster and other urchins, molluscs, at a lower latitude (Continental Drift: Tectonic Plate Theory). Sedimentary deposits of foraminiferans such as Globigerina and coccoliths (microscopic plankton with a calcium carbonate shell) lay down the chalk (Pic) which is rock of the South Downs near Shoreham.
Fossil bivalve  Spondylus spinosa (pic).

  • Santonian Age (87.5 to 84 million years ago). The age's name derives from the town of Saintes in western France, the area surrounding which is the classic type district for rocks of this age.

  • Chalk deposition in eastern England from Cenomanian to Maastrichtian time.
    Ref. for the chalk beds.

    60 million years ago, Tertiary (66.4 million - 2.3 million years ago).  Sussex is alternately covered by sea and tropical deltas.

    29 April 2020

    Sea Urchin Fossil, Echinocorys sp., from Brooklands beach, east Worthing.

    Photograph by June Bratton

    Shoreham-by-Sea: Geology

    25 March 2020

    Fossil from Shoreham Beach

    Alert children's eyes spotted this very small flint fossil amongst the billions of other pebbles on Shoreham Beach (by Beach Green). It is a bivalve mollusc from the Cretaceous period and the Natural History Museum suggested it could be the bivalve Limatula with representatives still extant today.

    Illustrated Report by Sam Ross on Shoreham-by-Sea & Southwick facebook

     PS: A very nice flint cast of a bivalve called Neithia from the Cretaceous chalk circa 85 million years ago.

    Second ID by Peter Mannering-Green on Fossil Identification UK  facebook




    Chalk Facts

  • Small internal mould of Echinocorys, preserved in flint    Fossil Sea Urchin Echinocorys scutatus
  • Chalk & Flint Link
  • Flintman on Flint (Link)
  • Other large fossils:
  • Aequipecten aspera     like a scallop impression
  • Aequipecten aspera  (Photograph by Andy Horton)

  • Ammonite Schloenbachia varians (pic.): particular level of chalk

    Hi Andy
    I'm replying as resident geologist!
    Schloenbachia varians comes from the Cenomanian, Lower Chalk of the Cretaceous Period. It is found commonly throughout the Lower Chalk of England and Northern Ireland though rare in Yorkshire. If this is not enough, please get back to me.

    John Cooper
    Booth Museum of Natural History, 194 Dyke Road BRIGHTON BN1 5AA U.K.
    John A. Cooper, Visitor Services Manager (Natural Sciences)

    Large ammonite  Acanthoceras rhotomagense  8 ft deep Upper Beeding (this is from the Upper Cretaceous, mid-Cenomanian, earlier deposits).

    from the  Marlipins

    5 June 2004

    The most interesting discovery was an unidentified fossil found on Shoreham beach and brought in by a young girl. This is illustrated above..

    The fossil is part of a test (internal shell) of a sea urchin formed about 85 million years ago. The long spines have broken off leaving the base only. The exact species has not been  established yet.

    It could be Prionocidaris vendocinensis but there are other species it could be as well.

    The flint probably formed from the dissolved remains of ancient sponge siliceous spicules and was deposited at a later date into gaps and beds in the chalk when the silica then solidified. When the friable chalk was eroded the flint remained, subsequently rounded into spherical and ovoid pebbles by the action of the waves grinding the pebbles against each other.

    Longshore Drift
    Adur Valley Nature Notes

    The Gault is a marshy clay. Paludal plants grow here on the alluvial river flood plains.
    Below the top layer of alluvium is a water-retaining sandy silt, known as marsh clay. However, there is plenty of chalk in the banks of the river, and this can be contrasted to the blue-grey of the marsh clay (or is this chalk with humus content?).

    The Albian Gault Clay, black and grey clays, contains a diverse marine fauna including ammonites and molluscs (incl. Spondylus), ichthyosaurs etc.
    Paludina Limestone is known as Sussex Marble. These are the little white outcrops amongst the Weald Clay.

    Reading Beds form small outcrops of gravelly soil. Raised beaches of flint occur in some areas, e.g.  Botolphs.


    The Lower Greensand is like a hard chalk and is also known as Malmstone. It is better for crops than chalk.

    Geology of London

    Link to the Old River Adur Course in Medieval Times


    Geology of Brighton to Worthing

    Page compiled by Andy Horton

    Shoreham-by-Sea  Homepage
    Shoreham-by-Sea  Page 2
    Shoreham-by-Sea 3: Wildlife Habitats
    Shoreham-by-Sea 4: More about the Town
    Shoreham-by-Sea Home Page
    BMLSS Home Page
    Shoreham-by-Sea 9 Diary of Events

    Sussex Archaeological Society

    (Link to) Cornwall (Prehistory, Geomorphology, etc.)

    Adur Valley

    Shoreham-by-Sea Homepage Link

    Shoreham-by-Sea 2 
    Modern map, Bungalow Town, Ancient Times
    Shoreham-by-Sea 4
    Housing, Historical Snippets

    Shoreham Lifeboat Station
    Link to the Adur Nature Notes 2007 web pages Shoreham Sailing Club 
    S Shoreham-by-Sea 7
    Marlipins Maritime Museum Adur Political Shoreham Beach
    Shoreham-by-Sea 8
    Shoreham-by-Sea 10
    Public Houses


    malm  | mm |  n. & v. [OE mealm- (in mealmstan) = ON malr ore, metal, Goth. malma sand, f. Gmc base also of MEAL n.1] A n. 1 (More fully malm rock, malmstone) a soft friable rock consisting largely of chalky material; light loamy soil formed by the disintegration of this rock. OE.  2 More fully malm-brick. A fine-quality brick made orig. from malm, marl, or similar chalky clay. E19. B v.t.  1 Treat (land) with malm. Only in E17. 2 Convert (clay) into artificial malm for brick-making; cover (brick earth) with artificial malm. M19.malmy a. of a loamy character L17.

    Excerpted from The Oxford Interactive Encyclopedia
    Developed by The Learning Company, Inc. Copyright (c) 1997 TLC Properties Inc. Seven SistersDowns above ShorehamSeven Sisters

    Geology of London
    The geologic foundation. The landscape of southeastern England is shaped by an undulating bed of thick white chalk, consisting of a pure limestone speckled with flint nodules in the upper beds. Under the chalk are an incomplete layer of Upper Greensand (a Cretaceous rock; 66.4 to 144 million years old) and a 200-foot- (60-metre-) thick waterproof layer of Gault clay. Beneath them in turn lies London's true geologic foundation, a stable platform of old hard rocks of Paleozoic age (about 245 to 540 million years old). This basement is buried nearly 1,000 feet below London, sloping away southward to depths more than 3,300 feet below the English Channel.
    The London Basin is a wedge-shaped declivity bounded to the south by the chalk of North Downs, running north to south, and to the north by the chalk outcrop of the Chiltern Hills, running up in a northeasterly direction from the Goring Gap. The chalk floor of the basin carries a sequence of clays and sands of the Tertiary Period (those 1.6 to 66.4 million years old), chiefly the stiff, gray-blue London Clay, which lies up to 433 feet thick under the metropolis and supports most of its tunnels and deeper foundations. The subsoil is topped with deposits of gravel up to 33 feet deep, consisting mostly of pebbles with flint, quartz, and quartzite. There are also patchy deposits of brick-earth, a mixture of clay and sand often excavated for building materials. Lastly, modern London is built on "made ground," the deposits of centuries of continuous human occupation, which have accumulated on average between 10 and 16 feet in the oldest urban nuclei of the City and Westminster.

    In England the Aptian Stage is represented by part of the Lower Greensand formation.

    Excerpted from Encylopaedia Britannica  CD-ROM  1997. 

    Paludal:    | pljud()l, -lu-, paljd()l, -l- |  a. E19. [f. L palud-, palus marsh + -AL1.] (Of a plant) growing in marshy ground, requiring a marshy habitat; Med. malarial; gen. marshy.paludine  | paljdn, -dLn; -l- |  a. of or pertaining to a marsh, marshy M19.