The Stones of Lincoln Cathedral EarthCache

The Building Stones of Lincoln Cathedral

 
Lincoln Cathedral stands on an escarpment of Middle Jurassic limestone.  The limestone was first quarried from the face of the escarpment by the Romans (1^st century AD) because of its ‘high place value’, to build a defensive hilltop fort.  Bishop Remegius used the limestone in 1072 to build the cathedral (his contemporaries used Caen stone for Rochester, Canterbury and Winchester Cathedrals).  Unfortunately, he built across a fault, resulting in the partial destruction of the cathedral in the earthquake of 1185.  The cathedral quarry is only about a mile to the north and work the limestone unit known as the ‘Lower’ Lincolnshire Limestone (or Silver Beds locally).  It is a strong building stone. Each supporting pier of the central tower carries 5500 tons!
 
The Oolitic Limestone
The main building stone in Lincoln Cathedral is the Inferior Oolite Lincolnshire Limestone. This stone is from a marine sediment formed in a warm shallow sea and made up of sand-sized egg-shaped “ooliths” in a calcite matrix.  The ooliths form around small grains, such as shell fragments which gather concentric layers of calcium carbonate (by precipitation) as they are rolled around the sea floor.  Their colour varies from pale cream/buff, pink (like streaky bacon) and blue-grey. When you look closely at the limestone with a hand lens or loupe, you should be able to make out the tiny spheroid particles held tightly together. These are the ooliths themselves.  The well-sorted, fine, even-grained fabric of the oolitic limestone provides the ‘perfect’ freestone (meaning it can be easily carved in all directions) making it an ideal stone for decorative carvings as well as for building. As well as the Cathedral itself, you will see numerous other buildings in the vicinity built of similar stone, such as the Exchequergate to the west of the cathedral and the Old Bishop's palace to the south.
If you venture inside the Cathedral you will be able to see other examples of stones used in its building. As you enter the main door at the West Front, you will be able to see much of this (eg the Font)without having to pass through the entry desk, at which point there is a fee. For example, many of the tombs mentioned below are far from view but you don't need to see these to complete this Earthcache.  
Other stone found in the Cathedral:

• Dark pillars of Purbeck ‘marble’ from Dorset was used by Bishop St Hugh (1185).  A polishing technique (lost later) brought out bronze, emerald and other colours. Later restorers used wood varnish to lacquer the stone with the disastrous results seen on the pillars. Note that this stone is not a true metamorphic marble but a finely packed limestone. It gets its name because it can be polished to look like marble
   
• The Tournai Font (SW corner of the Nave) is made from ‘Black marble’.  It was purchased between 1128 and 1148 and quarried and crafted at Tournai, Hainault, Belgium.  It is actually a very dark brown fossil-rich limestone with some green due to impurities.  The font stands on a modern base of Derbyshire Carboniferous limestone called ‘Ashford Black Marble’ because of its high carbon content.
   
• Remegius’ tomb slab (N side of nave) is made of carved Tournai marble.
   
• Choir screen under the central tower is made of stone on the south side but wood on the north.
   
• Tomb slabs in both aisles are those left from the 200 slabs and brasses before Cromwell’s hooligans vandalised the place in 1644.  They are post-Norman, many from Tournai, made from fossiliferous carboniferous limestone, some with high carbon content called ‘Blue Marble’.
   
• Purbeck Marble tomb slabs:
  • East end of north aisle (Bishop Chedworth 1452-1492)
  • South choir aisle (Bishop John Russell 1480-1496)
  • Langland Chantry Chapel, South side of the choir (Catherine Swynford, 3^rd wife of John of Gaunt)
  • In the choir stalls see the pre-14^th century dumb-bell shaped Purbeck marble slab let into the floor inscribed ‘Cantate Hic’ (“Sing here”) where the singer of Responds in the Choir stands to use the acoustics to best advantage.

• Retro Choir (behind main alter) more memorials:
  • Bishop Christopher Wordsworth, 1868-1885 - Portland Limestone
  • Dean William Butler, 1885-1894 - creamy white Triassic alabaster on reddish brown plinth.
     
• Route to coffee shop via cloisters:  left of the heavy door are two new shafts of Derbyshire Fossil Stone (Carboniferous Limestone), earlier ones are Purbeck Marble.
   
• Memorial tablets: Carrara Marble has been used for many but some are polished slate.
   
• Cloister Quadrangle gravestones:  The centre one (Bishop Edward King) is of grey Scottish granite.
   
• Bishop King’s statue (south transept) stands on a striking fossilised limestone plinth containing large corals.  This is believed to be Frosterley ‘Marble’ from Co. Durham as used extensively in Durham Cathedral.

To complete this Earthcache:

Email me with the following information:

1. From the listed coordinates, examine the stone from which the Cathdral is mostly built. 1) What is the name for this type of limestone? 2) Using your hand lens or loupe, look closely at the stone. a) Describe the typical shape, size and colour of the ooliths. b) Estimate how many ooliths can be counted in one square centimetre of stone. 3) Is this stone igneous, sedimentary or metamorphic in nature?

   Optional activity:Take a picture of yourself and/or your GPS unit beside any of the stone types mentioned above. Attach this to your post.
   
   Answers must be emailed to me in order to claim the cache, and an optional photo may be uploaded as suggested above. Logged finds with incorrect or incomplete answers may be deleted. There's plenty of traditional caches in the area for you to grab as well.
   
   Happy Earthcaching!

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