Cardiff Bay Urban EarthCache EarthCache

This EarthCache has been developed with the intention of introducing the Geocacher to the geology and some of the history (as it is written in the stones used) of Cardiff Bay. The area covered by this EarthCache is only a small part of Cardiff Bay, but it has been selected to include a number of different major rock types from a number of different locations.

Whilst this EarthCache has been set up with the support of the South Wales Geologists Association the accuracy of the content of the EarthCache description is the responsibility of the EarthCache owners. The South Wales Group of the Geologists Association, a registered charity, promotes Geology in South Wales through lectures, field meetings and publications. Membership is open to anyone with an interest in Geology. Click here to go to the South Wales Geologists Association Website. Use the 'back' button to return here if you click the link.

Traditionally the study of geology concentrated on examining hand specimens in the laboratory or visiting quarries and cliff exposures. These locations are often not available to the general public and are usually inaccessible to those in wheelchairs.

Some geologists seem to think that geology is in quarries, it is as if once the quarried products leave the site they are no longer geological! Yet the quarried products abound in towns and cities and are mostly ignored by geologists and the general public. It has been suggested that city geology walks are an ideal way of introducing beginners to the subject and require less organisation than traditional 'fieldwork'.

It is possible to find lots of 'exposures' of rock in the city. These are evident in civic buildings and churches, cemeteries and churchyards, statues, shop fronts, roads (especially the old cobbled variety) and pavements, roofs, garden walls and even rockery gardens. These can be used to study and teach geology in much the same way as we would if they were still in the quarry.

Whilst looking at the geology in a city it is also possible to study other related topics such as weathering and pollution. Some buildings have a date on them telling us when they were erected. This information can be use to study the weathering of the rock over a known time span. We can also study the effect of acid rain on carbonate rocks.

You do not need any special equipment to complete this EarthCache just, if it is raining, waterproof clothes or an umbrella, a notebook and a pen or pencil. A camera, magnifying glass or hand lens and a grain size scale or ruler would be useful but are not requirements.

Hammers, chisels, acid bottles, trowels, etc, are not necessary and are really not encouraged.

Please upload as many pictures as you want as long as they do not provide any of the answers to the questions associated with this or other nearby caches.

The intention is that the features described in this EarthCache are fully accessible to all Geocachers (see the text associated with Locations 11 and 12 regarding a route to avoid steps near the Compass Rose in Scott Harbour) at all times. However, because of events being held in Cardiff Bay, this may not be so. Access to The Senedd and associated areas may also be restricted for security/event reasons. Please do not cross any barriers should they be blocking the EarthCache route. Alternative routes are usually available.

Completing this EarthCache involves a walk of about 1 to 1 ½ kilometres (the exact distance depends on the closeness each feature is examined) from the junction of Bute Street and James Street to Roald Dhal Plass (formerly the Oval Basin), then to the Waterguard Pub, Scott Harbour and back to the start point. This should take about 1 ½ to 2 hours.

Where possible we have provided co-ordinates for the features described below. We have also given directions as GPS signals are not always reliable in urban areas.

The questions in this EarthCache relate to the geological features described and visited whilst walking this EarthCache route. Take time at each geological feature visited to examine the colour, texture, grain size, etc, (depending on how close you can get) of the stone. Please visit the area and do not simply try to find the answers by Internet research. Try to answer all questions. However, please give your reasons should you not be able to answer any particular question. As this cache is in an urban environment it will be subject to continual development/change.

To ensure that you visit the site and complete the walk through there is one logging requirement and four questions (these are detailed below).

We have presented the questions and logging requirements within the cache description text and collected them together at the end to help Geocachers who want just a single question and answer sheet. However, you will need access to the full text of the cache description in order to answer them.

Cardiff Bay lies 2km south of the centre of Cardiff.

By road, from the M4 junction 33, follow the A4232 signposted Cardiff Bay. Take the Techniquest exit, then follow the road ahead round to the traffic lights at the junction of Bute Street and James Street. Car parking (most of which is charged) is available in the area. There are frequent train services from Cardiff Queen Street station to Cardiff Bay station, also bus and train services from Cardiff Central station.

Map: OS 1:25,000 Explorer Sheet 151 (Cardiff & Bridgend).

A wide range of interesting and attractive stones can be found in the buildings of Cardiff Bay – Figure 1. The older buildings and docks are constructed of stone quarried from Wales and southern England. The newer buildings are concrete-steel structures clad with decorative stone, some of which comes from Wales, some from around the world. This walk looks at both the old and the new, at how the different stones formed, and at the development of Cardiff Bay.

This area forms part of the estuary of the Rivers Taff and Ely. Over the last 200 years, it has changed beyond all recognition. The docks were built between 1830 and 1907, the first (Bute West Dock) opening in 1839. Cardiff soon became an extremely busy international port. Millions of tons of coal, mined from the Valleys of South Wales, were exported through the docks. The last cargo of coal left Cardiff in 1964. Since then, the area has undergone considerable redevelopment, especially since the 1980s.

This walk takes you through part of Butetown. Although Butetown is a large area of Cardiff there is a small population compared to adjoining areas of Grangetown and Splott. The district can be split into four areas with James Street running through the middle. The area around Loundon Square is colloquial known as "The Bay" after Tiger Bay (though there are few buildings left from this era). This is in contrast to what the tourist call the Bay (actually in the Docks). The next area is Atlantic Wharf which is located in what was Newtown and the West Bute Dock, this is where Cardiff County Council are based. The next area is South of James Street or what the locals call "The Docks".

Until the end of the 18th Century this was largely an area of salt marsh and rough grazing, known as 'the Moors'. Butetown was constructed on reclaimed land and many of the buildings here are almost 'floating' on top of the mud flats. Ballast from incoming boats was used both in the foundations and construction of buildings. The Coal Exchange (where the price of coal on the British market was determined and the first million-pound deal was struck in 1907), in Mount Stuart Square to the west of our route, was the first building in the area to be built on piles, which were sunk into the ground to a depth of at least 9 metre. This was because the subsoils were alluvial mud mixed with slag from the old glassworks that had existed on this site, and when construction first started it was found to be a little like 'building on butter'.

The old Provincial Bank building (numbers 113 to 116 Bute Street – Figure 2), passed on the way to Location 2, was designed by FCR Palmer and WFC Holden for the National Provincial Bank and was constructed by E Turner and Son in 1924 – 1927. It is built of white Portland Stone. This stone was more desirable and prestigious than Bath Stone. It comes from quarries in the Isle of Portland in Dorset. Similar in origin to Bath Stone, it is a little younger in age.

Several of the older buildings in this part of Cardiff Bay are built of Bath or Portland Stone, with more exotic stones for decoration.

At Location 2 you should be in front of Pasco House, 54 Bute Street – Figure 3. Built in 1875 for the Powell Duffryn Coal Company, Pascoe House is an interesting example of one of the older buildings in Cardiff Bay. There is a better view from the back lane. The main part is grey sandstone, most probably Pennant Sandstone, from the Valleys of South Wales. The yellow buff stone, which has been carved and used to decorate the building, is called Bath Stone.

Bath Stone is a limestone, a sedimentary rock. It contains a lot of shell fragments and ooids (you could use a magnifying glass to see these small spherical grains), cemented together with calcium carbonate. It formed in warm shallow seas, as found in the Bahamas today. Bath Stone is a shelly detrital (bioclastic) oolitic limestone about 160 million years old (Middle Jurassic).

It comes from quarries near Bath.

The red stone, used along the bottom, the entrance steps and in the arches, is local Radyr Stone.

Radyr Stone is a breccia (another sedimentary rock). It contains irregular fragments of white, brown and grey rock. It formed in a hot dry climate where occasional torrential rain led to flash floods. These carried rock debris along wadis, which was then dumped as alluvial fans at their mouths. Over time, the fragments were cemented together with sand and calcium carbonate. It is of Triassic age, and is 210 million years old.

Radyr Stone crops out at Radyr, northwest of Cardiff. The quarries, to the west of the railway, were in operation from 1850 until the 1920s. As a local stone it has been much used in the Cardiff area, both for decorative and engineering construction. It is very distinctive.

The polished granite in the columns by the entrance is called 'Bessbrook granite'. This came from the Mountains of Mourne in Northern Ireland and is about 50 million years old.

The area you are walking through to get to Location 3 was originally all wetlands owned by John Crichton-Stuart, 2nd Marquess of Bute. He was persuaded to finance construction of the dock on his land at a cost of over £350,000. The dock opened under the name The Bute Ship Canal (later known as the West Dock or West Bute Dock) on 8th October 1839, and was over 1280 metres long and 60 metres wide, allowing 300 vessels to berth at any time.

The dock was joined by four others: East Bute Dock, Roath Basin, Roath Dock and Queen Alexandra Dock. Cardiff had become the largest exporter of coal in the world; in 1913, Cardiff exported 10,700,000 tonnes of coal. However, the Great Depression, Second World War and cheap foreign competition all caused massive damage to the Welsh coal mining industry, with the last coal export through the dock taking place in 1964. The dock was filled in to prevent collapse of the surrounding walls.

Location 3 is near ‘Craft in the Bay’ – Figure 4. This building, which was completed in 2002, is an old dock warehouse that has been moved and enlarged. The bollard in front is granite from the south west of England; it comes from the old Bute West Dock which once extended from the Bay along the length of Lloyd George Avenue.

From this point, you can see slate on the roof, in the pavement, and in the Wales Millennium Centre nearby (our next stop at Location 4).

Slate is a metamorphic rock. Metamorphic rocks form when already existing rocks are changed by heat and/or pressure, resulting in recrystallisation, usually with the formation of new minerals. Sediments, especially mud and silt deposits, can build up to great thicknesses on the sea bed. This can lead, over time, to the formation of shale (a sedimentary rock). Should this shale be buried even deeper, and subjected to increased temperature and pressure, recrystallisation of the constituent minerals can take place, forming the rock we call slate. In slate, the new minerals tend to be very small platy crystals which orientate themselves parallel to each other, at right angles to the direction of greatest pressure. This is why slate can be broken or ‘cleaved’ into parallel sheets, eg slates for the roof. If Earth processes tilt the sediments before they change into slate, the cleavage planes will be in a different direction to the original bedding.

Can you spot evidence of this in the pavement slates? Can you also spot the yellow pyrite crystals (fool’s gold)? This indicates that the original sediments were deposited in water containing no dissolved oxygen.

The slate on the roof of ‘Craft in the Bay’ comes from the Penrhyn Quarry at Bethesda, North Wales. The slate in the pavement is also from North Wales.

Both slates are about 500 million years old (Cambrian – Ordovician).

Cross the road to the Roald Dahls Plass (Oval Basin) and the Wales Millennium Centre.

Location 4 N 51° 27.879 W 003° 9.850

The Wales Millennium Centre is a prestigious international arts centre is clad in Welsh slate, reflecting and inspired by the geological features of the nearby coast. Phase 1 of the building was opened during the weekend of the 26th to 28th November 2004; whilst phase 2 opened on 22nd January 2009 with an inaugural concert.

There are five different colours and different textures (rough-hewn and cut) in the blocks of cladding, which are all slate waste from North and Mid Wales. The green and purple slates come from the Penrhyn Quarry. The dark grey rustic rusty slate comes from the Corris Quarry, north of Machynlleth. The plain dark grey slate comes from Ffestiniog. The colours result from slight differences in the composition of the slates.

To get to location 5 you are walking through Roald Dahl Plass (formerly the Oval Basin). What was known as the Oval Basin was designed (perhaps more correctly ‘redesigned’ in modern times) by artist William Pye, in conjunction with Nicholas Hare Architects, and it opened in April 2000. At the north end of the plaza is the Water Tower, which stands at approximately 21 metres high with a constant stream of water running down the metallic fountain. Roald Dahl Plass is today an oval shaped open space surrounded by illuminated pillars and has gravel covering over the original dock area. The plaza is often used to host concerts and other cultural events.

‘Why Roald Dahl Plass?’ Well Roald Dahl was born at Villa Marie, Fairwater Road in Llandaff, Cardiff, Wales in 1916, to Norwegian parents, Harald Dahl and Sofie Magdalene Dahl (née Hesselberg). Dahl's father had moved from Sarpsborg in Norway and settled in Cardiff in the 1880s. His mother came over to marry his father in 1911. Dahl was named after the polar explore Roald Amundsen, a national hero in Norway at the time. He spoke Norwegian at home with his parents and sisters, Astri, Alfhild, and Else. Dahl and his sisters were christened in Cardiff at the Norwegian Church (now relocated to Cardiff Bay), where their parents worshipped. In 2002 the Oval Basin plaza was re-christened Roald Dahl Plass. "Plass" means "place" or "square" in Norwegian, referring to the acclaimed late writer's Norwegian roots.

At Location 5 you are standing in a lock that ships passed through to get to the Oval Basin, which joined the Bute West Bute Dock and the Severn Estuary (there were two locks). Opened in 1839, some of the original stones must have since been replaced. For example Radyr Stone, quarried after 1850, is present in the basin walls. We would have liked to ask the question ‘Can you spot it?’ However, this is very difficult and we would not be able to verify the answers. Give it a go and see what we mean.

Granite is conspicuous all along the top of the basin, where it had to withstand the battering of innumerable ships moored alongside. This is a typical granite from the south west of England, with large white feldspar crystals in a finer mass of feldspar (white), quartz (colourless) and mica (both silvery and dark).

Granite is an igneous rock, formed when molten rock (magma) cools and solidifies. The crystals here are quite large. A long time is needed for them to grow, so this rock must have cooled slowly, which implies a great depth within the Earth’s crust. This granite formed 300 to 270 million ago (Carboniferous-Permian).

Pennant Sandstone, another sedimentary rock, is prominent in the dock walls. When fresh it is grey, but on weathering it has a brownish colour. It has a rough texture, like sandpaper, caused by the quartz present. It is the sandstone which covers much of the Valleys area to the north of Cardiff, forming the prominent steep scarp slopes. Pennant Sandstone is much used as a building stone in South Wales. The original stone for the dock was quarried around Pontypridd.

It was deposited as sand in northward flowing tropical rivers and deltas in the later part of the Carboniferous Period, around 300 million years ago. Note the ‘cross’ bedding, caused by currents in river channels.

Question 1. Where else is Granite conspicuous as you walk through the narrow part of Roald Dahl Plass/Oval Basin, that is the old sea lock, and why do you think it was used there?

At Location 6 you should be standing in/next to a public art called ‘A Meeting Place on the Plinth’ (by Richard Harris, 2006), a distinctive curving structure which emanates from the south side of The Senedd building’s plinth. From here you can see the Pierhead Building and The Senedd.

The Pierhead Building (on the left in Figure 7) is part of the estate of the National Assembly for Wales (the estate includes The Senedd (on the right in Figure 7) and Ty Hywel (the red brick building just visible behind The Senedd in Figure 7)). It stands as one of the city of Cardiff's most familiar landmarks and was built in 1897 (designed by Welsh architect William Frame) as the headquarters for the Bute Dock Company. The clock on the building is unofficially known as the "Baby Big Ben" or the "Big Ben of Wales", and also serves as a Welsh history museum.

The Pierhead Building has a French-Gothic Renaissance theme, and boasts details such as hexagonal chimneys, carved friezes, gargoyles, and a highly ornamental and distinctive clock tower. Its exterior is finished in glazed terracotta blocks supplied at the end of the nineteenth century by JC Edwards and Co of Acrefair near Ruabon in Wrexham - once described as one of the most successful producers of terracotta in the world. These features, along with the Pierhead's role in the development of the docks, Cardiff and industrial Wales earned it the status of a Grade One listed building.

On 1st March 2010, the Pierhead Building reopened to the public as a Welsh history museum and exhibition. Artefacts on display include the original binnacle (the stand housing the ship's compass) from Scott of the Antarctic's ship the Terra Nova.

The Senedd (in English: Legislature, Parliament or Senate - also known as the National Assembly building) was designed and built by a consortium of companies as follows: Contractor: Taylor Woodrow; Architect: Richard Rogers Partnership; Structural Engineer: Arup; Environmental / M&E Services Engineer: BDSP Partnership; Project Manager: TPS; and Quantity Surveyor: Northcroft. Work was started on the 1st March 2001 and completed on the 7th February 2006; whilst the building was inaugurated 1st March 2006 by Queen Elizabeth II.

The Senedd houses the debating chamber and three committee rooms for the National Assembly for Wales in Cardiff. The 5,308 square metres Senedd building had a total cost of £69.6 million, which included £49.7 million in construction costs. It was designed to be sustainable with use of renewable technologies and be energy efficient. The building was awarded an "Excellent" certification by the Building Research Establishment Environmental Assessment Method (BREEAM), the highest ever awarded in Wales.

The materials used to build The Senedd were as follows; the upper part of the roof is an aluminium standing seem roof with the underside being a woven timber soffit. The roof is supported by structural steel columns. The frame is constructed mainly from steel, and the outer walls mainly from slate and glass. The plinth (on which you are standing at Location 6) is made from reinforced concrete and slate. The Siambr desks and public gallery seating is made of Welsh oak.

Question 2. At the Wales Millennium Centre you were looking at a number of differently sourced slates. Compare these slates with those on The Senedd plinth, in particular with those that make up the art work ‘A Meeting Place on the Plinth’. Where do you think that this slate came from?

The Atradius Building is another of the new prestigious buildings in the Bay. Opened in 1995, it resembles the prow and sails of a ship. This building is described as having a decorative stone cladding of ‘Brazilian granite’. In fact there are two different stones, a light one and a dark one (with the trade names Samba White and Kinawa respectively). Look at the stones. Don’t they give the impression that the rock has melted and flowed? Note the small red crystals in the lighter stone; these are garnets (but of no commercial value!).

The relatively large crystals in both these stones, the banding, and the nature of the minerals, all indicate that they are metamorphic rocks that formed at very great depths in the Earth’s crust. Such rocks are called gneiss. Further evidence of the high temperatures and pressures that these rocks have been subjected to is shown by the plastic flow textures, and the irregular reddish bands in the dark stone which indicate that some of the rock has melted, possibly more than once. Hence, neither stone is granite!

Technically, geologists would describe the dark stone as a migmatitic biotitic granodioritic gneiss, and the light stone as a garnetiferous gneiss! Both are probably over 1500 million years old (Proterozoic). Both come from Bahia in north east Brazil.

The old part of the building which houses the Waterguard Pub was built in 1870 as the HM Customs and Excise House, since moved 50 metres to this location. The old part is constructed of grey Pennant Sandstoneand yellow buff Bath Stone. The new part, added in 2002, is built of fine grained cream Magnesian Limestone, supplied by High Moor Quarry, Tadcaster, Yorkshire.

Magnesian Limestone contains a large proportion of magnesium carbonate. It formed in a shallow tropical sea around 260 to 250 million years ago (Permian). Note the black dendritic patterns of manganese oxide.

We have brought you here to bring together themes (Scott, Dahl, Antarctica, the Geology of Cardiff Bay, etc) which have been running through the places visited in this EarthCache and because this location gives a very good view across Cardiff Bay.

Question 3 (proof of visit). Before we describe the location we have a proof of visit question. There is a plaque dedicated to the Waterfront Park (which you have been walking through) on the green adjacent to the ‘Antarctic 100’ Memorial. What are the names of the three organisations (in the order left to right) given at the bottom of the plaque?

The Scott ‘Antarctic 100’ Memorial is located between the Norwegian Church and the lock through which the Terra Nova emerged on its fateful journey south. The proximity to the little Church, originally built for use by Norwegian seamen, is a poignant reminder that Scott was beaten to the Pole by the Norwegian explorer, Roald Amundsen. The church is now deconsecrated and also acts as a reminder that the author Roald Dahl was a native of Cardiff.

The Scott ‘Antarctic 100’ Memorial was constructed in response to an initiative by the British Antarctic Heritage Trust to commemorate the 100th anniversary of the ‘Age of Antarctic Discovery’. The Captain Scott Society, in conjunction with the South Wales Echo, launched a prize for a sculpture to be erected in Cardiff Bay. The winner was Cardiff based sculptor, Jonathan Williams. The Memorial was formally unveiled by her Royal Highness, the Princess Royal, on the 6th June 2003.

The Scott ‘Antarctic 100’ Memorial is surfaced in an irregular mosaic of white and near-white tiles that ‘evoke the desolation and grandeur of the Antarctic ice’. The design represents Scott, man-hauling south towards the Pole while the faces of his colleagues can be seen trapped in the snow. The northern end of the statue reveals the foresails of the expedition’s vessel, the Terra Nova. An enigmatic cavern that pierces the structure represents the ice cave so vividly depicted in Ponting’s photographs of the expedition.

Now take in and enjoy the magnificent view across the bay. Looking out across Cardiff Bay you can start to see some of the geology that lead to the development of this area.

Sheltered by Penarth Head, Cardiff Bay has attracted sea traffic since the Middle Ages. Initially these boats could rest on their bottoms on the mud flats when the tide went out. By the 16th century, a brisk trade had developed along the South Wales coast, across the Bristol Channel, and onwards to France, Spain and Italy. By the 19th century trade extended worldwide to countries such as Argentina and India. As Cardiff exports grew, so did its population; dockworkers and sailors from across the world settled in neighbourhoods close to the docks and communities from up to 45 different nationalities formed.

With time also came the development of a need for a ‘floating harbour’ and hence the ‘docks’ with their sea locks controlling the water level. This in turn lead to the draining and filling in of the salt marshes and the reclaiming of the mud flats. Over time the Ely and Taff Rivers (which enter the Cardiff Bay on the far side from your observation point) were straightened and their former courses developed.

Cardiff Bay played a major part in Cardiff’s development by being the means of exporting coal from the South Wales Valleys to the rest of the world, helping to power the industrial age. The coal mining industry helped fund the building of Cardiff into the Capital City of Wales and helped the Third Marquis of Bute, who owned the docks, become the richest man in the world at the time. However, coal and other exports from the docks fell and eventually all this area was marked for regeneration.

In 1993 the Cardiff Bay Barrage was built to exclude the sea water from the previously tidal zone. The Barrage is an 800 metres long embankment of rock and sand and effectively creates a large freshwater lake with a 13 kilometre water front and has led to the regeneration of South Cardiff and Penarth.

Now what can you see of the geology of Cardiff Bay – we think very little as so much has been altered by man. Gone under the waters of the freshwater lake are the mud flats. Gone under the buildings, or converted into docks, are the salt marshes. Still there is the shelter offered by Penarth Head. What else remains is the ‘Building Stones of Cardiff’ which this EarthCache helps you explore.

Whilst walking along through Britannia Park and along the quayside you will come across the Beastie Benches (by Gwen Heeney, 1994) with inscriptions from the "Ballad Of The Long-Legged Bait" by Dylan Thomas.

Location 10 is near a commemorative plaque on your left as you enter Scott Harbour. This is named after Captain Scott, who was particularly well supported by the people of South Wales. His ship the Terra Nova sailed from near here for the South Pole in 1910. The buildings, completed in 1997, are clad in a distinctive red stone called Rapakivi Granite.

This type of granite is noted for its large rounded feldspar crystals containing rings of dark minerals. There are several ideas for its formation. One involves the effect of convection currents on the growth of the minerals in a slowly cooling magma deep inside the Earth. The rock is around 1500 million years old (Proterozoic).

The rock was quarried in southernmost Finland, sent to Italy for cutting and polishing, and then on to Wales. Its trade name is most probably Baltic Red ‘Marble’. A duller brown variety can be seen in some shop fronts around Cardiff.

As you walk towards the far end of the dock you will come to some steps. Walk up the steps and to the far end to reach the Compass Rose. As you walk through this area, note the (unpolished) paving slabs of the stones seen in the Atradius building.

The Compass Rose (by Sebastien Boyesen, 1997) is a paving mosaic constructed of many ornate decorative stones to commemorate Captain Scott's expedition to the South Pole, which sailed from Cardiff Dock on 15 June 1910 in the Terra Nova. The symbolism suggests exploration to the farthest reaches of the globe, but also refers to the spiritual dimension of Scott's journey, ideas of humility before vast challenges; honour, vision and destiny. The epitaph ("TO STRIVE, TO SEEK, TO FIND, AND NOT TO YIELD"), a quotation from Tennyson, which appears on a cross in Antarctica where Scott and his colleagues met their deaths, forms the centrepiece.

"TO STRIVE, TO SEEK, TO FIND, AND NOT TO YIELD" would also be a good Geocaching motto. We hope you enjoyed completing this EarthCache.

Question 4. The Compass Rose is constructed of many ornate decorative stones. Can you identify the predominate stone and metals used in its construction?

Question 5. Having identified the stones used in the construction of the Compass Rose, which one may cause problems here and why must you ‘TAKE CARE’ here (see a bright red sign)?

We have collected the questions and logging requirement together so that they can be copied and pasted onto a single sheet should you want a paper version. However, you will need access to the full text of the cache description in order to answer them.

Question 1. Where else is Granite conspicuous as you walk through the narrow part of Roald Dahl Plass/Oval Basin, that is the old sea lock, and why do you think it was used there?

Question 2. At the Wales Millennium Centre you were looking at a number of differently sourced slates. Compare these slates with those on The Senedd plinth, in particular with those that make up the art work ‘A Meeting Place on the Plinth’. Where do you think that this slate came from?

Question 3 (proof of visit). Before we describe the location we have a proof of visit question. There is a plaque dedicated to the Waterfront Park (which you have been walking through) on the green adjacent to the ‘Antarctic 100’ Memorial. What are the names of the three organisations (in the order left to right) given at the bottom of the plaque?

Question 4. The Compass Rose is constructed of many ornate decorative stones. Can you identify the predominate stone and metals used in its construction?

Question 5. Having identified the stones used in the construction of the Compass Rose, which one may cause problems here and why must you ‘TAKE CARE’ here (see a bright red sign)?

Email the answers to the Questions 1 to 5 to us via the link in our profile. Please do not put the answers to the questions in your log entry, even encrypted. You do not need to wait for a reply before making your log. However, we request that you email the answers to us on the same day that you make your log. Any logs that do not fulfil all requirements will be deleted.

Photographs from your visit are very welcome with your log. Feel free to upload any, except those that assist in answering the Questions, photographs you take during your visit to the EarthCache site in Cardiff City centre. We may even replace the current Figures using your pictures.

Please let us know (either in your log or through our profile) what you think of this urban EarthCache – was it useful in extending your knowledge of geology, was it too difficult, or any other constructive comments.

Picture credits are given under the appropriate Figure. If there is no credit we took the picture.

We would like to thank the South Wales Geologists Association for their assistance in setting up this EarthCache.

The Cardiff Public Art Register, 1st Edition 2008, used to identify and provide details for some of the sculptures listed.

Public Monument and Sculpture Association National Recording Project website, used to identify and provide details for some of the sculptures listed.

Wikipedia, used to provide details for some of the locations listed.

Fletcher Morgan website, used to provide details for some of the locations listed.

BBC website, used to provide details for some of the locations listed.

We apologise if we have, unintentionally, omitted any information source.