Building London has covered a number of limestones used in London before and Ancaster is another one that was much used in the 19thC. It’s a beautiful stone with rich honey and buff and sometimes blueish streaks that has earned it the nickname ‘streaky bacon’.
Ancaster is one of the Lincolnshire Limestones, and, as the name tells us, it is only quarried in the area around the village of Ancaster, on Ermine Street, north-east of Grantham in Lincolnshire.
It has been quarried since Roman times, no doubt using their incredible road system to distribute, and then in the mediaeval period was widely used for religious and important buildings in the surrounding areas. Cambridge has a number of old buildings built with Ancaster stone.
Local quarry firm Goldholme state “Ancaster played an important role in the early years of Cambridge and was used in Kings College Chapel in 1480. In the 19th century Ancaster stone found favour once more across Cambridge including the Gothic revival chapel at St Johns College. The buildings of Tree Court at Gonville and Caius College. Following a fire in 1852. Trinity Hall was rebuilt in Ancaster Stone plus the re facing of Peterhouse old court. One later example is the medieval school at the Sedgewick Geology Museum 1901 to 1904 built with Ancaster Ashler stone. Ancaster was such an important stone that it became under Royal control in the 14th century due to the massive building project at Windsor Castle.” 
The British Geological Survey in the Lincolnshire Building Stone Atlas states “The Lincolnshire Limestone has been quarried for building stone along the full length of its outcrop, at some localities since at least Roman times (e.g. around Lincoln, Ancaster, Heydour and Stamford). By medieval times, Lincolnshire Limestone was being extensively transported eastwards and southeastwards along a fairly elaborate system of waterways for use in the monastic sites and other ecclesiastical buildings of the Fenland(s) (e.g. Crowland Abbey). In the 17th and 18th century, these quarries gradually expanded in order to satisfy not only Lincolnshire’s demand for limestone but that of the adjacent counties and areas beyond, including Cambridgeshire (e.g. Ely and Peterborough cathedrals), Norfolk, Northamptonshire, Rutland and even Suffolk.”  Ancaster’s location allowed it access via the Trent or the Fen rivers to coastal ports for wider distribution. 
St Albans Cathedral  had some Ancaster stone from the mediaeval period but the whole of the west front of was re-faced, controversially, with Ancaster in 1880.
Building London has not seen specific Roman or mediaeval uses of Ancaster on London yet, but with the stone apparently going up the Thames to Windsor, it seems unlikely some would have not been used in London itself, and in 2019, Ancaster was indeed, for the first time, identified in Roman walls at the Tower of London, by Howard and Roberts, where it had not been previously thought to be before… “… this more detailed petrological investigative approach has for the first time picked out rare (Ancaster freestone) … to Roman London … A quarter of the large blocks are from the Lincolnshire Limestone outcrop (Middle Jurassic — Bajocian) and include some late Roman … and Ancaster freestone … from central Lincolnshire. The discovery of so much Ancaster stone was surprising given that before now their identification was restricted to a single tombstone of a child from Crosswall Bastion B4a (Marciana), a sarcophagus from Harper Road, Southwark and an item of religious sculpture from close to the Temple of Mithras…” 
Ancaster did though became very popular in London in the ‘Gothic Revival’ of the 19thC, being used in the ‘gothic’ masterpiece of St Pancras , Lincoln’s Inn Chapel, Holborn Town Hall among many other, inc. the Clapton Round Chapel which will be the part 2 of this post.
What is Ancaster Limestone?
Ancaster limestone is a “… Middle Jurassic oolitic limestone, quarried around Ancaster, Lincolnshire… There are three forms of this limestone: weatherbed, hard white and freestone. Ancaster stone is a generic term for these forms of limestone found only at Ancaster”  
The BGS Lincolnshire Building Stone Atlas describes it as “The typically coarse-grained, creamy white to yellow-orange, ooidal and bioclastic limestones that characterise much of this formation are by far the best known of Lincolnshire’s vernacular building stones. … The uppermost bed of the sequence is known as the Ancaster ‘Ragstone’ or ‘Weatherbed’ (2–3 m thick), and comprises cross-bedded, pale yellow (but occasionally reddish), ooidal and bioclastic limestones. Underlying the ‘Ragstone’ are the ‘Hard White’ and the ‘Freestone’ beds, which have a combined thickness of c. 3–4 m. The ooidal ‘Hard White’ limestone, as its name suggests, is sufficiently well-cemented to provide a marble-like polished finish. The ‘Freestone’ beds are in general less coarsely fossiliferous than those of the ‘Ragstone’, and they provided much of the high quality block required for the ashlar and decorative stonework of churches and monastic buildings.” 
The term ‘Ancaster’ is too vague as there are 3 different beds: The ‘weatherbed’ or ragstone, the ‘hard white’ and ‘freestone’. The incredibly useful ‘Stone in Archaeology Database’  separates them out, noting there can also be specific beds within beds, and that they can be cross-bedded, just to complicate things for the quarrier and user! 😀
It describes the 3 main beds, in descending order, as:
1. “Ancaster Rag / Weatherbed Inferior Oolite Group, Upper Lincolnshire Limestone Formation…Colour varies from cream to brownish yellow (due to oxide of iron staining) and through to a blue/grey colour. The stone can be mottled and/or flecked … A medium grained, hard, shelly limestone containing ooliths and small rolled gastropods, it may be pistolitic in places …Several beds are important, the upper ‘Red Weatherbed’ commonly reddened in colour and the lower ‘Brown Weatherbed’ which is a warm brown colour. Both stones are coarsely shelly and hard wearing and take an excellent polish. In quarry sections they can be strongly cross-bedded. In colour the beds of the Weatherbed sequence can vary and often show a lenticular core of blue grey limestone (often known as ‘blue hearted’) (Purcell 1967)… This is the hardest of the Ancaster stones” 
2. “Ancaster Hard White Inferior Oolite Group, Upper Lincolnshire Formation…Pale honey to cream colour…medium grain, hard, well cemented oolitic limestone … uniform texture and very little shell” 
3. “Ancaster freestone/freebed, Inferior Oolite, Upper Lincolnshire Formation … cream to pale brown/buff in colour … – compact, medium grain, predominantly oolitic containing a few shell fragments” 
The Streaky Bacon is the Weatherbed,  as specimens of Ancaster stone at the John Watson Building Stones museum show. 
The Open University Geological Society explain the streaks as: “The weathered Ancaster Limestone is characteristically described as streaky bacon due to the variations from changing water levels, currents and chemistry during deposition. Deposition took place in clear, agitated, shallow water in which lime was precipitated as both ooliths and pistoliths. There are also shallow water bivalves and gastropods are associated with colonial algae and corals. Oolite shoals were moved and redeposited by currents, and cross stratification is preserved in the bed forms.” 
Search ‘Ancaster’ to see other examples and old pictures of the quarries here > http://geoscenic.bgs.ac.uk/asset-bank/action/viewHome
At the Glebe quarries there are thick layers of clays and mudstones and shales of the Upper Estuarine Series,  now called The Rutland Formation covering the limestone.  
Both those links are also good guides to the quarries, see below.
There are 4 working quarries now, Castle, just east of Ancaster, Copper Hill just to the south on Ermine Street and 2 neighbouring quarries variously called Glebe and Gregory’s. Building London visited 3 of these working quarries in early 2022.
There’s also what may be a very interesting and historic quarry in a woodland just north of Glebe quarries, which was also Ancaster and/or Glebe Quarry, but it is now a wooded SSSI and was pretty off-limits and no one knew how to contact the new owner. Another mediaeval Quarry is just to the south at Quarry Farm and was know as Thompson’s. There is also a farm called Pits Hills Farm which suggests historic quarrying, which as this blog has noted elsewhere were usually initially for surface rock, whether at Dartmoor or Collyweston. And there was a 19thC railway side ‘stone pit’ at Pottergate Road but I can find no references to that stone being used anywhere. And there was a Lindley’s but that may be Gregory’s under a different owner. 
The Castle Quarry is thought to be one of the most historic, from it’s previous name as Castle Pits, and is now run by Goldholme  This quarry is mainly for building stone of various types. They have a really useful set of walls to show the different stones and was great to be shown that and have the different stones described. The Stone in Archaeology website states “On the 1891 O.S. Map this area is known as Castle Pits and at various periods in history on this site has been found Roman coins and a tesselated pavement.” And that it was quarried in the “Post Medieval” period as well as now. It states the Glebe Quarry was quarried in “Roman, Early Medieval,” period. 
A recent planning document for the extension of the Copper Hill Quarry states “ White’s Gazetteer of .. 1856 .. the entry for Wilsford describes the produce of its quarries as ‘beautiful, white and durable freestone, commonly called “Ancaster Stone” from its first being worked in that adjoining parish, more than 500 years ago… Of this stone, many of the churches, public buildings and large mansions in this county have been erected’ … The 1872 edition of White’s Gazetteer lists the Ancaster Stone Company and two stonemasons among the businesses of Ancaster, but still notes that its stone quarries are in Wilsford parish (p.650). Kelly’s Directories of 1889, 1896 and 1900 were also consulted, but only the Ancaster Stone Company, operating solely in Wilsford parish (out of what is now the Castle Quarry) could be identified.”  Copper Hill Quarry is in Ancaster parish and not Wilsford Heath.
Permission was given to drive to the bottom of the large Ancaster Copper Hill Stone Ltd quarry and take some photos of the old quarry walls which maps show are almost certainly are from the 19thC.
The visit to the Glebe pit of Terry and Andy Smith, aka Gregory’s Quarry, was the best as bumped into Terry Smith and his team, and was given a great history of the industry and allowed down into the quarry to get some great photos of the different beds so a massive thanks to Terry for that!  
Glebestone at the Ancaster Quarry, just south-east of the the Glebe Quarry was not visited.  They state they provided Ancaster Freestone that built Holborn Town Hall in 1894 and 1906.  
There’s not that much to see at Ancaster unless you book in to visit the various quarries, and they’re working quarries and they’re not set up for visits, though you can at least walk up to Castle Quarry from Ancaster and look at the demonstration walls. And while Ancaster is a stone village it’s not ‘Cotswolds pretty’ though it’s interesting with small old stone cottages lining what was Ermine Street.
St Martin’s Church is worth a look, dating back to the Norman period, and is of course built of Ancaster Stone,   and interestingly is built on the site of a Roman Temple and there is a Roman statue, a copy actually, in the grounds, of the Deae Matres, female deities. The original is in Lincoln Museum with other Roman finds from the village.  This walk from Hugh Marrows passes two Roman sarcophagi in Ancaster Cemetery, inevitably of Ancaster stone. 
Roman remains were apparently common in the 19thC but anything found ended up sold or some at least put in museums. Remains are now all underground.  Time Team did some digging there in 2001. 
But Ancaster does has a fascinating geological feature, The Valley, thought to have been created at the end of the last Ice Age, which while fairly small is really beautiful and in spring and summer is covered in amazing flowers. Lincolnshire Wildlife Trust says “A steep sided valley covered with limestone grassland, scrub and woodland. It is one of the finest sites for limestone flowers in the country.”  Well worth a visit!
Ancaster, surprisingly for just a village, is on the rail network. It’s an hour and 40 minutes from Kings Cross to Ancaster via a change at Grantham or a slightly longer journey via Sleaford.
Cycling, as above from Grantham or Sleaford. It’s a c45 minute ride from Grantham and less from Sleaford.
And by road from London it’s c.2 1/2 hours up the A1 and Ermine Street.
 “Defending Londinium and the Tower of London: the raw materials. A petrological re-evaluation of the fabric of the wardrobe tower and adjoining roman defensive structures at the Tower of London.” Transactions of the London & Middlesex Archaeological Society . 2019, Vol. 70, p105-128. 24p. Hayward, Kevin M. J.; Roberts, George W.
[ You’ll need to join LAMAS to read the full article https://www.lamas.org.uk/join-lamas.html ]
 https://buildinglondon.blog/2021/12/20/23-the-john-watson-building-stones-collection-at-the-sedgewick-museum-in-cambridge/  https://ougs.org/london/event-reports/658/field-trip-the-scarplands-of-lincolnshire-from-the-lincoln-edge-to-the-wolds/