St James Church at Husborne Crawley
There was probably a church here in Anglo-Saxon times though nothing of that date remains. The first surviving mention of a church in Husborne Crawley is in 1170 when it was granted to Dunstable Priory. By the beginning of the 20th Century, the fabric of St. James had fallen into a bad state of disrepair. With the exception of the tower, most of the church underwent extensive restoration and rebuilding in 1911, funded by the Duke of Bedford, though the rebuilding did make extensive use of the original components.
What really makes St James Church unique, is the appearance of the building stones used. Like most churches along the Greensand Ridge it is built from local sandstone, for both accessibility and cost. The church is located on a pronounced ridge of Lower Greensand, suggesting that the bedrock here is resistant. It is possible that the late medieval church builders simply excavated part of the hillside. To date, the source of this unique sandstone remains unknown. Continue through the graveyard to enjoy the viewpoint.
Greensand Country
The Greensand Ridge stretches for 40 miles from Cambridgeshire in the East, across Bedfordshire and to Buckinghamshire in the West. This distinctive area, known as Greensand Country, contains all of Bedfordshire’s remaining heathland, more than half of it’s woodland and has more historic parkland than anywhere else in the country. This EarthCache looks at the sandstone found in this area.
What is Sandstone?
Sandstone is a sedimentary rock composed of sand-size grains of mineral, rock, or organic material. It also contains a cementing material that binds the sand grains together and may contain a matrix of silt- or clay-size particles that occupy the spaces between the sand grains. Sandstone is one of the most common types of sedimentary rock and is found in sedimentary basins throughout the world. Here in Bedfordshire, we have different coloured sandstone rocks, from golden tan to orangey-red, through to dark brown and even green!
Why all the different colours?
Sand grains can be any colour from almost pure white to black. Most of Bedfordshire’s sandstones consist of grains of quartz (a form of silica) but one special type of sandstone has grains of glauconite. Glauconite is an iron-rich mica mineral that is green in colour.
Sandstone colours can also be different due to the impurities within the minerals that bind, or cement, the sand grains together. The most common colours are clear, tan, brown, yellow, red, grey, pink, white, and black. Common cementing minerals include silica and calcite which are clear coloured minerals, but others are hematite, goethite, limonite, feldspars, anhydrite, gypsum, barite, clay, and zeolite minerals.
Oxidation (rusting) of iron minerals cementing the particles together can turn the sandstone various shades of orange, red and brown. In some instances, there is a purple hue caused by manganese.
To log this EarthCache please complete the following tasks, as detailed below. Answers will be accepted via email through my Geocaching profile or using the Geocaching Message Centre. There is no need to wait for an answer to log the cache. Please do not mention the answers in your logs, nor include detailed photos of the church walls.
St James Church at Husborne Crawley is built from three very distinctive types of sandstone. Go to the observation waypoint to the right of the church porch where a second door is located on the south facing wall. If this area is currently in the shade, move to a sunny spot for the best observations.
1. Describe and compare the three different sandstones in the church wall, a sunny spot on the south facing wall is ideal for this. Detail the colour, observe the grain size, feel the texture and comment on the hardness of each. For simplicity, let’s call them Sandstone A, B and C.
2. Suggest the predominant reason why each of the sandstones before you is the colour it appears.
3. There are two shades of the same colour, which even appear as a layer on the same building block. Why do you think this happened? Suggest a possible reason for this occurrence. What effect do you think this had on the characteristics of the two sandstones?
4. As part of the requirements to claim this find, please attach a photograph of yourself with the church in the background to your log. Bonus points for originality! If you prefer not to include your face, your hand will be adequate or your GPS.
Special thanks to the Greensand Trust and Bedfordshire Geology Group for their advice and guidance.
I hope you have enjoyed this EarthCache and learnt more about the geology of Greensand Country.
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Congratulations to Pesh for FTF
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For full information on how you can expand the Church Micro series by sadexploration please read the Place your own Church Micro page before you contact him at churchmicro.co.uk
See also the Church Micro Statistics and Home pages for further information about the series.
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