After St Mary-de-Lode church, turn left into Archdeacon
Street. Head down towards the end of the street then bear left into Westgate
Street. Opposite St Nicholas's Church (which, incidentally, has a leaning
tower) is Nicki's Taverna. The marble-like stone beneath the windows has
an amazing pattern. This is Rapakivi granite and has large round feldspar
crystals in cross-section. It's probably the oldest rocks we'll see on
this walk, dating from Precambrian times (543 million years ago to 4500
million years ago!). What's so special about this granite is that it's
a metamorphic rock - it solidified after an original melt, remelted and
then recrystalised.
Discover more...
Alan talks about the rare example of Rapakivi granite on this building.
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Shire Hall on Westgate Street |
Continuing up Westgate Street towards The Cross, our
next stop is Shire Hall. Here we'll see two very different stones which
offer valuable insights into geological history. The front of Shire Hall,
designed by Sir Robert Smirke in 1816, is made from Pennant Sandstone
from the Forest of Dean. This stone began life being deposited in carboniferous
coal swamp deltas about 295 million years ago. You'll notice that there
is some red staining on various blocks - this is due to iron oxide in
the stone. Also, you'll see pebbles embedded within the sandstone at various
points. These stones are called Siltstone and are less resistant to weathering,
which is why some of them have disappeared completely.
Discover more...
Alan explains more about the sandstone to be found on Shire Hall.
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Facing Shire Hall, head right and follow the building
around to the side. You'll now see the modern part of the hall, added
in the 1960s. The materials used here document a violent time in Britain's
history, for the green panels that stretch down the side of the building
were once volcanic ash deposited in the Lake District. This happened about
460 million years ago in the Ordovician Period. In some panels you can
see the layer of ash from one eruption followed by another layer of ash
from a subsequent eruption.
Discover more...
Alan talks about the example of volcanic stone from the Ordovician
period.
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Return to Westgate Street and resume your journey up
towards The Cross. The last stop before you reach The Cross is the Halifax
building society on your right. This building is faced with a material
called Serpentinite.
Discover more...
Alan talks about the Serpentinite on this building.
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Finally you've returned to The Cross and the end of this
walk. The Cross is the meeting point of the four main streets that follow
the original Roman foursquare plan laid down around 45AD. Gloucester city
centre was subsequently developed by following civilisations but the original
Roman design of four-squares from The Cross still holds true.
...And now you've completed the short walk around
Gloucester city centre. If you have any comments to make or would like
to send any Gloucester Trail pictures in, please visit the Feedback
page.
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