Harrow and Hillingdon Geological Society
Uxbridge Walk
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Uxbridge Building Stones
Our own Jo Crocker lead us on a superb trip of the building stones in Uxbridge. It is amazing what wonders we step over and walk past while doing our shopping. Here are some of the fascinating things we saw.........
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Portland stone used for the railway logos over the station. This is Freestone, meaning free from fossils, and thus very easy to carve. The logos represent the wheels and springs of a railway carriage. |
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A belemnite with phragmacone. This was in the Jurassic limestone flags in the Chimes. This limestone comes from Germany and is bioturbated which gives it an interesting pattern. |
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Rapakivi granite found on the tables in Cafe Gardino in the Chimes. The crystals formed spheres while cooling from the magma. This is a slow process and concentric rings are formed. The green colouration is a reflection from a light in the cafe. |
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The church doorway. Old original flints are large and not uniform in size. These are above the door arch. In Victorian times repairs were made but using smaller, more uniform and better napped flints. The arch is probably made from Reigate stone - a greensand and prone to weathering. |
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We had a bonus to our tour. The church door was opened by a woman who agreed to let us inside. This carving is mainly in alabaster, a type of gypsum. |
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In the floor of the church we found a sponge. |
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Reclaimed granite sets and curb-stones found in the High Street. Note the large feldspar crystals in the sets. The rough dimpled surface is where some crystals have weathered out over time. |
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Outside the Pavilions we found Carboniferous limestone from Derbyshire. This is very muddy, hence the dark colour, and rather disappointing. Much Carboniferous limestone has wonderful fossils of crinoids and sponges, but this just had a few bits of shell. |
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The famous 'McDonaldite' found facing McDonald's outlets throughout the known universe. It is a young rock (50 - 100 years old) called travertine, and is formed by the precipitation of calcium carbonate in pools (in the same way that kettles get furred up) where hot water springs from the rocks. Any organisms that like living in these pools get precipitated upon and incorporated into the rock, giving it an interesting wavy texture. This travertine is from Italy. |