Green Geology

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Useful links:

 

Peterborough Museum and Art Gallery

 

Peterborough Cathedral

 

How to get there:

Rail or coach

 

Nearest railway station:  Peterborough

 

Accessibility:

Smooth pavements, lift available in Museum

Text and photographs:  Naomi Stevenson

Text and photography (c):

Naomi Stevenson

 

Photo of Pachycostasaurus dawni online by kind permission of Peterborough Museum and Art Gallery.

 

Page updated June 2013

Peterborough, on the edge of the Fens, is not famed for mountainous scenery and abundant outcrops of rock.  Nevertheless, local stone is much in evidence in local buildings in a compact area of the city centre, as is a variety of rock from further afield in England and abroad.  The Peterborough Geology Trail starts at the newly-refurbishes Museum and Art Gallery on Priestgate – which is within easy walking distance from the railway station and is worth visiting in its own right for its geological and fossil displays.  A guide to the trail is available here.

 

In addition to stone from elsewhere in England and further afield, the Geology Trail showcases local stone.  The pillars at the front of the museum are carved from Lincolnshire limestone - as are the door surrounds.  The shelly limestone used for the museum walls was quarried at Clipsham, near Stamford.  

 

Leaving the museum and walking down Priestgate towards Bridge Street, a good example of the traditional local roofing material is easily seen from close up on the porch at Yorkshire House which is currently occupied by Ask (a restaurant).  This stone is Collyweston slate, actually a Lincolnshire limestone that splits into slate-like sheets as a result of frost action.  

 

The cathedral forms the geological heart of Peterborough, as well as its ecclesiastical and historic heart.  It is largely built of a shelly Lincolnshire limestone known as Barnack Rag; the quarry it came from, Barnack Hills and Holes, is now a National Nature Reserve designated for its wild flowers.  

 

Inside the cathedral, a local limestone known as Alwalton Marble, formed from oyster shells, was used for effigies including St. Benedict’s and was used for the upright of the font.  The upper part of the font is made from Purbeck Marble - this is also a shelly limestone rather than a true marble.  The sanctuary area and the High Altar and canopy showcase stone from further afield – the altar stands on steps of Italian pavonazzo marble; the canopy and the wall behind the altar are made from Derbyshire alabaster, with the canopy supported by pillars of Belgian marble.  Steps of Frosterley Marble and a red Italian marble, Rosso Levanto, front the mosaic bays of the Sanctuary.

 

Queensgate shopping centre is floored with limestone rich in ammonites and belemnites with less frequent sponges and corals.  The cream-coloured limestone comes from Germany; the greyer rock was imported from Italy.

 

The Town Hall, on Bridge Street, is fronted by Triassic sandstone pillars.  These are rather eroded but stratification can still be seen.  

 

The trail also takes in many volcanic rocks:  The kerbs in the area of Ask, on Priestgate, are carved from a deep red Leicestershire volcanic rock, and when you reach Bridge Street more volcanic rocks can be seen.  Larvikite, a Permian syenite with iridescent feldspars (Labradorite) is used as a facing material on various banks and former banks and at the former Burton’s shop on Bridge Street.  

 

Cornish granite, which looks grey from a distance but which consists of a mixture of white plagioclase feldspar, grey quartz, and dark muscovite mica, has been used for several buildings.  The HSBC bank at the corner of Bridge Street and Cathedral Square is a good place to look at it closely.  

 

Another igneous rock, Rapakivi granite, is used at the Westgate exit from Queensgate shopping centre and at the base of the escalator near John Lewis.  This is a very old rock with a complex geological history; the large pink feldspars were enclosed by a green variety of plagioclase feldspar, cutting and polishing the rock (as for ornamental use!) shows this very clearly.

 

Long Causeway is a good place to see red granites, which gain their colour from the composition of the feldspars they contain, as well as for seeing further facades of Cornish granite.

 

Metamorphic rocks have also been used in Peterborough:  Welsh slate can be seen on the roof of a row of shops on Wentworth Street, and true marbles were used in several places within the cathedral; for example Thomas Deacon’s tomb is carved from Italian Carrara marble.

 

The trail ends with another variety of Lincolnshire limestone – Wittering pendle, a thin, golden limestone which is waterproof enough to have been used for flooring stables – was used to build what is now Carluccio's on Cathedral Square.

Peterborough Geology Trail

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Peterborough museum