Out on the bleak North Sea coast marshes of Essex stands the abandoned Beaumont Quay, sat forlornly at the end of the mile long silted up tidal Beaumont Cut  that sliced through the estuary mud, marsh lands and hundreds of islands of the massive Hamford Water National Nature Reserve and RAMSAR site  
The quay is a mile and a half north of the Saxon village of Thorpe-le-Soken, ‘soken’ meaning the parish had some of their own legal jurisdiction that lasted remarkably till the 19thC in an area owned by St Pauls from the 12th to the 16thC.   but then bought as an investment in the early 18thC by Guy’s Hospital. 
Beaumont Quay can never have been that busy, with some occasional trade exporting cheese and hay to towns along the coast and down into London, in exchange for incoming cargos of horse dung and ‘night-soil’ from those towns and cargos of chalk to be burnt in an old lime-kiln to create lime, all for improving the farmers fields.
Apparently the phrase was “Hay in, muck out”! ‘Stackies’ sailed from creeks like this with a haystack lashed down on deck, bound for London and it’s horses; the barges would reload wth manure and bring it back to the farms – a perfect trading symmetry” 
But clearly it did enough business that in the 1830s, with bits of the Old London Bridge stone on offer, Guy’s decided to both dig a straight channel through the marshes, the Beaumont Cut, and build a solid stone quay from that stone, Beaumont Quay.
The excellent Victoria County History describes the history as:
“In 1577 a list of all the ports, havens, creeks and landing places on the Essex coast recorded a creek, three landing places and four customs deputies at Thorpe-le-Soken and Beaumont. One of those landing places is likely to have been near Beaumont Quay and another one at Landermere Wharf in Thorpe. Such landing places were used to export agricultural produce such as corn, hay, and cheese from local farms like Beaumont Hall to London.”
“In 1727 they [ Guy’s ] commissioned a survey of Beaumont Hall prior to their purchase, which not only recommended it as a very good buy, but noted that there were two “very convenient landing places for bringing chalk rubbish from Kent and carrying of corn or any other thing off to London”. This neatly describes the two-way traffic to London, with corn being taken to market and soil improvers being brought back as the return cargo – in this case chalk but just as often horse manure and ‘night soil’.”
“In 1831 London bridge was demolished and replaced, and Thomas Guy’s Hospital acquired some of the old stone blocks which it transported to Beaumont to build a new quay in the following year. The quay was about 80 metres long, partly of stone (unmortared) and partly of timber. In addition, the governors paid for the digging of a new channel or canal called Beaumont Cut, two metres deep and about 1km long which linked the quay to deeper water in Hamford Water. A basin at the quay allowed barges or other vessels to turn around, and in 1848 it was described as navigable for vessels up to 70 tons.” 
There was a limestone plaque from 1832 on the store building stating
This BUILDING and QUAY
was erected by the
GOVERNORS OF GUYS HOSPITAL 1832
HARRISON Esq Treasurer
The Stone used in the Quay formed part
of London Bridge built about
but sadly this has been gone for a number of years and I understand it’s ‘whereabouts are unknown”. 
What is it made from
The big interest of the Building London blog is in the material used in buildings and their source and where they end up and interestingly, while there is agreement that these blocks are definitely from the Old London Bridge, the various surveys are not in agreement what stone they are, and sadly, as a non-geologist, I can not say either way.
Some references just say the stone is ‘ashlar’ i.e cut blocks as opposed to rough shaped ‘ragstone’, some merely as “blocks”, one reference states vaguely “ragstone or limestone”, one states they are Sarsen stone and another Merstham aka Reigate Stone. So what are they?!
John Moore for the Colchester Archaeological Group states, “The stone section is constructed of massive ashlar blocks, the largest being 92cm x 53cm x 34cm.” .
Historic England state “The stone part of the quay is constructed of massive blocks laid in four courses forming a frontage 25.7m long … The blocks, between 0.4m and 1.0m long, 0.4m or more deep and 03m or more thick, are unmortared but many are held together by iron staples. The stone was salvaged from the demolition of London Bridge and many of the blocks exhibit sockets which may date from this earlier use”  
Heritage Gateway state “The quay is built with a facing of tooled ashlar (ragstone or limestone) with post revetment further along” 
The British Geological Survey, in their Essex Building Stone Atlas suggests that Beaumont Quay is built from “ .. Sarsen Stone taken from Old London Bridge which was demolished in 1831” 
[ Nb the BGS Building Stone Atlases are a Urban Geologists dream! 😀 though I am still waiting for the London / Middlesex one, but that is a mammoth task and it may be some wait!  ]
Sarsen stones “ …. are the post-glacial remains of a cap of Cenozoic silcrete that once covered much of southern England – a dense, hard rock created from sand bound by a silica cement, making it a kind of silicified sandstone. This is thought to have formed during Neogene to Quaternary weathering by the silicification of Upper Paleocene Lambeth Group sediments, resulting from acid leaching.” 
Katy Whitaker, in her (2019) ‘Sarsen stone quarrying in southern England: an introduction’ states: “Sarsen is a silcrete found in central-southern and eastern England, formed by the accumulation of silica in near-surface Tertiary sediments. The silica, likely carried in groundwater, cemented quartz sands into indurated masses. Following periods of erosion which removed uncemented material, and later movement under periglacial conditions, the remaining cobbles and boulders can now be found both exposed on the surface in sarsen spreads … and buried in superficial deposits (such as the clay-with-flints south of Eynsford, Kent). The silica content is usually greater than 95% … Archaeologists tend to divide sarsen into two categories based on macromorphological characteristics … The hard, grey sandstone boulders familiar from the settings at Avebury and Stonehenge are known as saccharoid sarsen because the freshly-broken surface looks like sugar-loaf. The second type, quartzitic sarsen, is formed of finer sediments and commonly found as smaller cobbles and pebbles, browner in colour” 
Sarsen’s are famously the hard stones that stand in the Avebury and Stonehenge stone circles and are most commonly found on the chalk downs of Wessex, but also the South Downs, and in areas around London including the Chilterns, Essex and North Downs, not so far from where the Kentish Ragstone and Reigate Stone was being quarried for Old London Bridge. Kit’s Coty, and Little Kit’s Coty, the remains of a Neolithic Long Barrows, were made from Sarsen/Silcrete and are remarkably close to where Kentish Ragstone would have been being mined in the 12th/13thC. 
The eponymous Wealdstone in north west London is a Sarsen! 
As a very tough stone, found in areas that were accessible for London, it is very possible that that is what the blocks at Beaumont Quay are.
However I am making a calculated guess that it is the Essex Field Club, both for their probable specialist local and geological knowledge and from what I have learnt about what Old London Bridge was made from , who have most correctly identified the stones….. as Merstham Stone.
They state: “Beaumont Quay has another feature of geological interest. The stones forming the edge of the quay are from the old London Bridge, constructed between 1176 and 1209, which was the first London Bridge to be built of stone. The bridge stood for over 600 years, finally being demolished in 1831, with some of the stone coming here to Beaumont Quay. The stone is called Merstham Stone, better known as ‘Firestone’, a fine-grained sandstone of Cretaceous age from the Upper Greensand of Merstham in Surrey.” 
And we do know that large blocks of Merstham Stone were used in the Old London Bridge so there is a logic there too. See 
Merstham Stone is often also called Reigate Stone  and they appear generally to be the synonymous or analogous but together they are described in a number of different ways.
The excellent Reigate Stone Research Project states Reigate Stone is .. “neither a limestone, nor a sandstone; nor is it (as it is usually described) a calcareous sandstone, as very little of the silica in it is in the form of detrital sand grains; Reigate stone is in fact a unique building stone type in Britain…” 
But John Ashurst in his ‘Conservation of Building and Decorative Stone’ states “The Upper Greensand (Lower Cretaceous) around Reigate, Merstham, Gatton and Godstone in Surrey contains beds of compact sandstones…” 
Graham Lott and Don Cameron in their excellent ‘The Building Stones of South East England” state “The Reigate Stone is quite variable in its mineralogy, but essentially comprises a highly porous framework of siliceous sponge spicules with variable proportions of detrital quartz, glauconite and mica … ” 
And Martin Michette states “Early characterisations of the building stone noted roughly equal proportions of silica and calcium carbonate … Whilst it has been referred to as both a siliceous limestone and more commonly a calcareous sandstone, Sanderson and Garner state it cannot truly be classified as either.” 
Use on London Bridge
But whatever it is technically, we do know clearly that Merstham, or Reigate, stone was used extensively in Old London Bridge!
Michette notes that “From the mid-twelfth century onwards the use of Reigate Stone became more prevalent … It was chosen for detailed masonry in the construction of the priories and abbeys emerging across the city, but use is also documented in secular buildings … Starting in the 1170 s, it was used in the construction of two bridges crossing the Thames, at Kingston and further downstream at the first stone-built London Bridge… The loss of the French possessions in 1206 is likely to have limited the ongoing use of Caen Stone. The first half of the thirteenth century sees the establishment of several new quarries around Reigate and stockpiling sites along the Thames…” 
As does Martin Hatton in his two articles reproduced by the Croydon caving Club “Reigate Stone was also used in the building of London Bridge from 1176 (Schofield,1994). “ and “in 1461 John Ropkyn supplied Merstham Stone to London Bridge”  And again “Hence we find in the London Bridge accounts for 1461 “for 47 loads of stones called Reygateston at 20d the load at the quarry of Maistham 78s4d” (Harding & Wright,1995,p126).” 
John Watson in his seminal 1911 British and Foreign Building Stones states “Merstham Stone, from the Upper Greensand in Surrey, which is better known as ” Firestone,” has for many centuries been employed for building construction. It is a fine-grained sandstone containing a large amount of colloid silica, very porous, and remarkable for its fire-resisting qualities. So much importance was attached to this that the quarries were at one time the exclusive property of the Crown, and the stone was employed only in the erection of royal and ecclesiastical buildings. Old London Bridge was constructed with this stone (1176)…” 
But for me possibly the clincher in what this stone is [ in the absence of an actual geological survey! ] is that one of the characteristics of Merstham/Reigate Stone that would have made it eminently suitable for Beaumont Quay AND why it is in such good nick after 600 or so years is … “A final quality from which Reigate Stone has been said to benefit is that “if kept either always wet or always dry, [it is] very durable” … Whilst the word ‘very’ when applied to the durability of Reigate Stone might be questioned under almost any conditions, it certainly seems that builders exploited this quality… Examples of ‘always wet’ include its use in bridges (e.g. London Bridge …), quays (e.g. that at Westminster …)” 
In my opinion there needs to be a proper geological survey as there is a strong circumstantial argument for these stones being either Mertsham and Sarsen stone! I will continue to investigate and report back! 😀
Of course the function of a quay is trade and trade was done using sailed barges and sadly at the end of the creek there is the decayed remains of a one such barge, The Rose, built in nearby Maldon in 1880, based at Maldon, then Leigh on Sea on the Thames, then sold for use as a housebarge in 1961 and transported to Beaumont Quay, where it was destroyed by fire and now settles year by year into the Essex estuary mud.  
Two barges were actually known to be based at Beaumont Quay “ … the 44-ton Beaumont Belle, built by Howard of Maldon in 1894 and owned in 1911 by Alan Stanford of Beaumont Hall, and the 30-ton Gleaner built at Limehouse in 1897, also for Alan Stanford”  while another, Mercy, was a regular visitor. Beaumont Belle ended up as a hulk at Maldon apparently, Mercy is still said to be visible at Heybridge but I can’t see where The Gleaner is. 
Desolate and bleak can of course be wonderfully scenic and Beaumont Quay is indeed a great places for long, or short, walks!
Here are two good inspirations for you!
Beaumont Quay has also recently developed a reputation for ‘wild swimming’ but I think seeing as it is so muddy you would have to be pretty careful and only swim at and shortly after high tide. . Green Parent states re Essex, “The best places for summer dipping are Beaumont or Kirby tidal quays… At Kirby-Le-Soken a walk across two fields leads to a pontoon and beach. Even better is Beaumont Quay, near Thorpe, built in 1831 using the 12th century stones of the old dismantled London Bridge. From here, brown topsails drifting out across the flat marsh skyline, flat bottomed barges would set sail loaded with haystacks for London’s horses, and return with manure for the Essex fields. Now at high tide this is an idyllic swimming spot.” 
Thanks – thanks to Maria Medlycott, MA, MCIfA, FSA, Senior Historic Environment Consultant at Essex County Council for providing me with some documentation from the 1990s that is not online.
It’s relatively easy to get to Beaumont Quay from London by public transport. Trains go to Walton on the Naze, Frinton, Kirby Cross or Thorpe le Soken regularly from Liverpool Street.
A nice walk would be from Walton up to Harwich, via Beaumont Quay.
Driving, Beaumont Quay is not far off the A120 and A12, and there is free parking there.
If you can’t visit this You Tube drone video from John Edwards shows the quay and Rose https://www.youtube.com/watch?v=UGe2ZNdKyI8
 https://en.wikipedia.org/wiki/Beaumont_Cut#/media/File:Beaumont_Cut.png “The original uploader was Old Moonraker at English Wikipedia…”
 from “The many faces of Reigate Stone: an assessment of variability in historic masonry based on Medieval London’s principal freestone” https://heritagesciencejournal.springeropen.com/articles/10.1186/s40494-020-00424-w
 Pelobates – issue 88 – March 2010 Martin Hatton The Exploitation, Distribution and Use in Buildings of Reigate Stone pt2 https://www.croydoncavingclub.org.uk/node/391
 Pelobates – Issue 87 – Feb 2009 Martin Hatton ‘The Exploitation, Distribution and Use in Buildings of Reigate Stone pt1’ https://www.croydoncavingclub.org.uk/node/380
 “British and Foreign Building Stones. A Descriptive Catalogue of the Specimens in the Sedgwick Museum, Cambridge. By John Watson.” https://archive.org/details/britishforeignbu00watsrich/page/246/mode/2up