Before logging this cache, please send us the answers to the questions below
The chapel of St. Peter-on-the-wall, first appears to be, from a distance, of simple basic construction. It is however of great interest for two main reasons, it is probably the oldest church in England of which so much of the original building remains, and it is also the last monument to the short-lived Anglo-Celtic Church of the old East Saxon kingdom.
The chapel was built by St. Cedd, who it is believed, sailed down the East Coast from Lindisfarne, landing here in the estuary of the River Blackwater ( formerly known as the River Pant, like it's inland source). Construction of the chapel took place in the years immediately after his arrival in 653 AD, on the site (wall) of the old Roman Othona fort, hence the name St. Peter-on-the-wall. It is a lasting legacy of St. Cedd's influence in the East Saxon kingdom, before he succumbed to the plague in Lastingham in 664 AD.
It was used regularly as a place of worship until sometime around 1700, when it was converted for agricultural use, and a number of changes were made to its appearance, with new doors (since filled in), cut in the both the north and the south walls.
The chapel was re-consecrated on the 20th June 1920, and is the site of an annual pilgrimage in July, which is attended by up to 800 people. Sunday services are held regularly throughout July and August, and a service of Holy Communion is held once a month.
The chapel is built mainly of reused materials from the old fort, although the roof was renewed in 1947, and there is the obvious newer infill of the doors referred to above.
Some of the materials used in the construction of the chapel, are shown in the images below.
They are, in order - Kentish Ragstone, Pink Oolitic Limestone, Roman Tiles, Tufa Limestone, Flints.
Limestone is one of the most common natural building materials in the world, and Oolitic and Tufa limestones are just different forms of this mineral. All limestones are formed of calcium carbonate (mainly calcite, and aragonite), but from different origins.
Oolitic limestone was formed in a warm shallow sea during the Jurassic period ~135 million years ago. Under magnification it can be seen to have an even grained appearance, with many small spheroidal – or egg shaped - ooids, on which rings of calcium carbonate have built up around the core, cementing the ooids together. It’s colour varies from white, through cream, to pink, depending upon the impurities present.
Tufa limestone is generally of fresh water origin, often where springs flowed into a lake. It is a softer, spongier, and more porous form of limestone, than Oolitic limestone. This is due partly to the method of formation – loss of carbon dioxide from the spring water as it entered the lake thus leading to precipitation of calcium carbonate (calcite), and partly because of inclusion of detritus from the water into the limestone.
Kentish Ragstone is a hard, well cemented, and sandy glauoconitic limestone. It is found in the Hythe formation, part of the Lower Greensand Group of the Weald basin. Formed under shallow marine conditions during the Cretaceous period some 145 – 65 million years ago, building quality material is found in beds rarely more than 90 cm thick. Colours vary from light grey through dark grey, sometimes as far as sandy brown, and all weather to different shades. The 14C Westgate Towers in Canterbury are a good example of the durability of Kentish Ragstone.
Flint is a hard crystalline form of silica, and is a variety of chert. It is found chiefly as nodules or masses in limestone and chalk. The silica was originally formed during the late Cretaceous period some 60-95 million years ago, from siliceous sponges and planktonic micro-organisms. This silica then gradually replaced some of the calcium carbonate within the sediment of the chalk sea bed by chemical action, transforming to hard, nodular flint, over a long period. Flint does not have a regular crystal structure and so does not fracture cleanly when struck, or when split by the effects of frost and ice in any cracks.
Roman Bricks, often called tiles, were made from fired clay just like modern bricks. The key to brick making, in geological terms, is the mineral content of the raw material, and this is common to all clay types. Clay mineral is formed from the erosion and weathering of primary igneous rocks, this material is transported by the action of water, wind, ice etc. and re-deposited elsewhere. In the process it picks up a number of impurities, such as Quartz, Mica, Calcium Carbonate (lime), Iron Oxide etc. The subsequent deposit then, over time, becomes a sedimentary rock which is then quarried and processed into bricks. Roman bricks came in a variety of shapes and sizes (unlike the mainly standard sized bricks we see today), and were used both as building materials in their own right, and as bonding courses. They were often made in mobile kilns, and many were stamped with the identity of the Legion that made them. The Romans ruled Britain from 43-410 AD, but after they left, much of their building material was reused in later buildings due to the shortage of materials available .
Before logging this cache, please send us the answers to the questions below
Q1. At N51 44.120 E000 56.390 What is the material of the three stones adjacent to the door handle, what colour is it, and in what time period was it formed ?
Q2. At N51 44.124 E000 56.399 What is the material of the obviously damaged dark coloured stone about three feet from the ground, and just to the right of where the buttress used to be, and what do you think caused the damage ?
Q3. At N51 44.124 E000 56.406 What are the curved row of stones, coming down from just below the meeting of the courses of stone and brick, what type of rock was quarried to make clay, and approximately how old are they ?
Whilst it is not necessary to enter the chapel to complete this cache, it is open to visitors, however please remember it is still a place of worship.
Grateful Thanks are extended to the Chapel Committee of the Chelmsford Diocese, for permission to place this cache.