Some twenty foolhardy members and friends of the Essex Rock & Mineral Society and Essex Field Club braved a thoroughly wet and miserable morning at Maylandsea to look at the London Clay exposure. Thirteen souls went on to spend a windy afternoon at Steeple Bay to examine the London Clay foreshore.

London Clay:
London Clay stretches from Great Yarmouth, where it has been proved in boreholes to Wiltshire in the west and the Isle of Wight in the south. The deposit is about 50,000,000 years old and has a maximum thickness of 150m.The deposit underlies London and has been extensively bored through in the construction of the Underground tube lines. Sediments, which formed the London Clay, are representative of a fully marine environment at a depth of approximately 150m.

Maylandsea: 


This site is situated on the eastern bank of Lawling Creek and has yielded a vast number of crustacean remains. The exposure is at TL 907435, the low cliff running for a distance of about 225 metres and the actual foreshore platform being approximately 600 metres in length. Erosion has been quite rapid here in the last 25 years. A layer of large flattish septarian nodules is prominent at the southern end of the exposure. The 2 or 3m of London Clay exposed in the low cliff and foreshore here belongs to the middle of Division B about 30m above the base of the deposit.

The clay is possibly only a metre or so above the “Isselicrinus zone”; rolled specimens of which may be found in the beach gravel and which may be found in vast quantities on Northey and Osea Islands nearby.

The London Clay facies at Maylandsea represents the time of maximum depth of the London Clay sea. Deeper water species are found here that do not occur at Sheppey or elsewhere (Dineley & Metcalf 1999 pp 504, 508-90.

After a brief discussion, reprints of an article about the site were distributed and searching of the cliff, beach and foreshore commenced in a flurry of hectic activity. Our visit to this site lasted about an hour and many fossilized sharks’ teeth and lobsters were found. (Specimens in August's Meeting notes). Shards of Romano- British pottery, mainly domestic cooking vessels, and various teeth and bones were found on the beach, no doubt washed from the soil at the top of the 2m or so high cliff. From time to time, Mesolithic and Neolithic flints including microliths and arrowheads may be found on the beach.

Steeple:

Some 13 members of the party mustered on the beach at Steeple by courtesy of The Steeple Bay Caravan Park who kindly allowed us to drive along their private road and park near the sea wall. Further off prints were handed out. Fortunately the rain stopped and the gale force winds soon dried out our sodden clothes. The buffeting, blasting, bracing breeze blew over a few lighter members of the party. It is an odd feeling being blown along while ones feet are stuck in the sticky mud.

Finds included many fish teeth including Otodus obliquus and Rhinoptera. Many fine lobsters, including an undescribed species, similar to Hoploparia, but with a well defined ridge either side of the middle of the carapace, were found. Artifacts collected included several flint Mesolithic waste blades and flakes.

The foreshore exposure of London Clay stretches from just below the shingle and gravel beach in front of the sea wall and low cliff of marsh clay down to low water mark. To the west the site is bounded by Mayland Creek which runs northwesterly. To the north Lawling Creek, which flows north easterly forms the boundary from its confluence with Mayland Creek. The eastern limit of the exposure is ill defined due to the variable amount of recent river mud and sand. The gently sloping platform is largely formed of weathered stiff brown London Clay with occasional patches of very weathered and largely disintegrated cement stone nodules. The nodules are flattish and do not exhibit the well-defined calcite lined septa of Sheppey specimens. The fossils listed below, appear to be concentrated both around the patches of nodules and among the gravel concentrations on the foreshore. They are most abundant at about TL 916043. The fauna would indicate that the London Clay here, as at Maylandsea may be assigned to the lower part of King’s (1970) sedimentary rhythm B. Cylindrical phosphatic nodules appear to be concentrated in certain areas particularly around TL 917042, while cement stones are quite common in front of the low cliff of marsh clay at TL 917043.

It is of interest that Steeple nodules were being sold in the 1820s for making Roman cement at Sheerness. An agreement made 30th May 1828 between James Northwood and Robert Laver on the one part and Jeremiah Brown on the other part for the sale of clay nodules on Canney Farm shore survives at the Essex Record Office [D/DCm E11].

A series of recent deposits, which rest on the London Clay, fringe Mayland and Lawling Creeks from about TL 917041 to TL 914043. Peat and marsh clays are quite well exposed and a fine array of Mesolithic and Neolithic artifacts has been collected from the beach gravel. These include tanged-and-barbed arrowheads, flint knives and scrapers and a splendid quartzite mace head. The London Clay platform here has great potential.

Steeple Church: Two members of the party visited the nearby parish church of St. Lawrence and All Saints, Steeple. (I suspect all the others were stuck in the mud or blown out to sea, or was there a pub/cafe nearby? RC) The cement stones were evidently used for local building purposes also. The parish church previously stood 150 yards (about 137m) south of Steeple Hall where the churchyard is still enclosed. The new church was built in 1882 on a site 600 yards (about 548m) further east and incorporated much of the old building material. A great deal of cement stone may be seen in the external fabric of the church giving a most pleasing effect. Interestingly stems of the sea lily Isselicrinus subbasaltiformis (Miller 1821) may be seen in some of the cement stone nodules especially on the eastern wall of the chancel as well as the north and west walls. Several of the nodules are bored by the modern calcareous sponge Cliona celata (Grant) which indicates that some of the stone was originally collected from the beach.

References:
Dineley, D.L. & Metcalf S.J. 1999. Fossil Fishes of Great Britain.
Geological Conservation Review Series.

George, W.H. & Vincent, S.W. 1977 A foreshore exposure of London Clay at Steeple, Essex Tertiary Research vol. 1(4) pp. 105-107.

George, W.H. & Vincent, S.W. 1982 An exposure of London Clay at Maylandsea (Lawling Creek), Essex Tertiary Research vol. 4(2) pp. 39-41.

King, C. 1981 The Stratigraphy of the London Clay and associated Deposits Tertiary Research Special Paper No.6.

Bill George (020 8594 6817 william-george@lineone.net) 20th August 2001

Many thanks to Bill for penning this field trip article. There is a lot of information contained here that should help guide you if planning a trip. Bill is one of the Society's leading lights on the Geology of Essex. He, probably more than anyone else, knows virtually all the published papers relating to the Geology of Essex and has done much more field work than he lets on. If you want to know more about Essex Geology and need to "hit the deck running” I recommend ESSEX ROCK by Gerald Lucy. Get a copy!

Members, would you like to pen an article for our Website? Don't be put off by Bill's professional approach. Give it a go! I've heard most of you articulating clearly about your pet rocks and fossils. Put it in black and white or what ever colour you like. (RC 22/08/01)

Previous Trips:
Kensworth & Stewartby
Roxwell & Barrington
The Naze Walton