Thatcham has evidence of occupation dating from prehistoric times and is listed in the Guinness Book of Records as the strongest claimant to being the oldest continuously inhabited place in Britain.
Berkshire lies on the north west side of the London Basin and the Berkshire Downs formed from the Upper Cretaceous Chalk mark the northern edge of this basin. The chalk outcrop slopes gently away to the south and is succeeded by sands and clays of Tertiary age which form the central part of the basin.
The Chalk was laid down in a shallow sea during the Upper Cretaceous (beginning about 100 million years ago). The rock is made up of the calcium carbonate remains of mollusc shells, foraminifera and coccoliths. The absence of any terrestrial input of mud or sand suggests that the chalk was laid down a long way from the contemporary shore line. The chalk dips gently to the south with its exposed upper (northern) edge forming the ridge which runs from White Horse Hill at Uffington to the Thames north of Goring. This long escarpment is the most striking physical feature in the county and is indented by numerous winding valleys, most of which are dry and produced by terrestrial erosion during the Ice Age. The chalk passes south under the valley of the Kennet and then reappears at the surface to form a second scarp under Inkpen Beacon. The chalk forms the bedrock in the east of the county and Windsor Castle stands on a small folded dome of chalk.
In many areas the surface of the chalk is covered by clay with flints. This represents what was left after the prolonged erosion and weathering of the chalk during the Tertiary period.
South of a line from Hungerford, via Reading to Windsor, are Tertiary deposits of clays and sands laid down in shallow marine, coastal and fluvial environments. The Tertiary sediments belong to the Lambeth Group and comprise sands (the Upnor Formation) deposited in a shallow sea overlain by the reddish-brown clays of the Reading Formation. These latter sediments were deposited on marshy mudflats crossed by river channels and outcrop in a narrow strip between the Chalk and the overlying London Clay.
To the south and east of Newbury the London Clay is overlain by the sandy Bagshot Formation. This is exposed on the scarps of many small ridges along the Kennet Valley although most of this is overlain by Plateau Gravel. The best exposures are in a band extending from Finchampstead Ridges to Virginia Water in south east Berkshire. The Bagshot Beds were laid down as a consequence of the shallowing of the sea which formed the London Clay and comprise of red sands, pipe clays and a coarse, pebbly, current-bedded sandstone. A patchwork of later river gravels lies on top.
St Mary's Church. St Mary's Church has undergone many changes architecturally during its lifetime. Originally built of wood, the first stone structure was built by the Normans in circa 1140. It is thought to have looked like this;
Subsequent additions and extensions ( as detailed in the link above) have created the Church as we see it today
The Tower itself is very interesting with a clear demarcation of the two periods of building; one up to the level of the South Aisle roof, and one above ( by the window line).
Illustrations from the St Mary's Website ( link above)
In order to log this Earthcache please email me answers to the following questions;
1. At Waypoint 1, the side of the Church ( South Aisle) meets the Tower. They are constructed of two types of building material.
a) Please name the two types of material.
b) Compare their appearance and qualities and describe the differences.
c) Give an explanation of how one of the types is formed and why it has been used on either the wall or Tower.
At Waypoint 2
On the rear wall of the Church are two distinctive types of building material either side of the downpipe marking the two stages of building.
a) What are the main colours in the right hand side materials and suggest a reason for the colour difference between the wall here and the material used in the Tower.
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