Eglwys bach y mor (Little Church in the Sea) EarthCache

On the small tidal island called Cribinau located off the south-west coast of Anglesey and close to the village of Aberffraw there is just one structure - a church. St Cwyfan's Church is commonly known as the Church in the Sea, and also known as Llangwyfan. It can be reached on foot at low tide.

The original site or "Llan" of Cwyfans would have been founded in the 7th Century and the building would have been of wattle and daub construction. The present building is said to date back to the 12th or 13th Century with the building undergoing many restorations. Some Norman masonry remains in the South wall, however the main body is 14th Century. The arched, braced roof timbers are partly 16th century. By the 19th Century the building was a roofless ruin but money was raised to repair the building and to build the massive sea defence walls that give the island it's distinctive shape.

In the 21st Century the church was in the news when Cadw (the Welsh Government’s historic environment service) offered a grant to repair the building. The grant was conditional on the exterior of the building being finished in a cream coloured limewash. Locals were not happy with the colour scheme with many preferring the weathered look of the old building. However Cadw prevailed and St Cwyfan's Church joined the many old Welsh buildings to receive the fashionable limewash finish. In 2008 the church was in the news again when an organ was presented to the church that had to be carried across the causeway by church wardens and local farmers.

Old Jacobean maps dated 1636 show the church standing on the mainland of Anglesey but erosion by the sea of the boulder clay cliffs has since separated the church from the mainland. Coastal erosion is the wearing away of land and the removal of beach or dune sediments by wave action, tidal currents, wave currents, or drainage.

There are four main types of coastal erosion. These are:

• Hydraulic action: Air may become trapped in joints and cracks on a cliff face. When a wave breaks, the trapped air is compressed which weakens the cliff and causes erosion.
• Abrasion: Bits of rock and sand in waves grind down cliff surfaces like sandpaper.
• Attrition: Waves smash rocks and pebbles on the shore into each other, and they break and become smoother.
• Solution: Acids contained in sea water will dissolve some types of rock such as chalk or limestone.

A coastal defense has been installed on the island to reduce the rate of erosion (a sea wall surrounding the church and graveyard).

This cache aims to give an insight into coastal erosion and how it is being slowed down with the use of coastal management strategies, as well as showing you an example of this happening in real life.

To claim this cache go to the island at the listing co-ords and email me the answers to the following questions:

Research:

• Name one other type of Coastal Management strategy other than a sea wall that could have been used to protect the church and the graveyard.

At GZ:

• How long do you think it will be before the sea wall will need to be replaced/repaired? What evidence is there at/near GZ to support your answer?
• Estimate the distance between the island and the mainland to discover how much the coastline has eroded.
• Using information from the listing and your answer to the previous question, work out an average of how many metres the coast erodes away every 10 years at this location.
• Feel free to upload photos of you and the island. (Not required but desirable)

There is no need to wait for a reply to the email you send me. If you do not send me an email within 1 week of putting a 'Found' log on this page then it may be deleted.

As this is a tidal island it is not available to get to all of the time. View the tide times here to see when it is available.

Please Note: Previous visits to the island DO NOT class as finds - you must have visited after 27th August 2013.