Downquay Gardens is situated at the bottom of Quay Road, opposite the Trevaunance Cove car park in St Agnes. Until 2011, Downquay Gardens was an area of wasteland beside the coast path until it was given to the village and transformed by local volunteers to create the gardens. There are a number of benches overlooking Trevaunance Cove, which makes it an excellent picnic spot.
From the open area, there is a good view of the remains of St Agnes harbour at low tide.
Since the 17th century, there have been many attempts to create a harbour for St Agnes - all with limited success. From 1632, the lords of the manor of Trevaunance made three separate attempts to build a harbour. Their third harbour was washed away in 1705 together with their family legacy. The harbour was rebuilt in 1710 by others and lasted 20 years before being levelled in 1730 by the Atlantic waves. In 1798, a new harbour was constructed which was to last for over 100 years. This supported a fishing industry and allowed for the export of copper ore and the import of coal from South Wales for the smelters at the mines. St Agnes remained a busy port until the collapse of the harbour wall in a storm in 1915/16, after which it was never rebuilt.
Harbour walls created from mortared square blocks of granite during the Victorian period very quickly become unstable when the mortar between them is eroded by the sea. The large square blocks are particularly susceptible to the hydraulic lifting effect of the sea and the receding waves can suck loose blocks out of the harbour wall.
The previous old-fashioned way of building drystone harbour walls from unshaped boulders stacked on their edges did not suffer this problem, as the hydraulic pressure would be released through the gaps between the stones and the narrow, rounded bottom of each one did not present the sea much surface area to lift against.
The metallic minerals associated with outcrops of granite tend to occur in bands which radiate out from the granite outcrop. A band of tin deposits usually occurs closest to the granite, then beyond this a band containing copper ore. A band of zinc and lead deposits is commonly found further away from the granite, with just iron at the furthest extreme. The reason for the banding is that the deposition of each mineral occurs within a specific temperature range. Granite starts as a molten blob of magma which cools very slowly and provides a source of heat. The temperature of water in the cracks in the neighbouring rock therefore decreases with increasing distance from the hot granite.
The mine workings to your right were part of Wheal Kitty. Some of the old engine houses have been converted into residential buildings, and the area is also the headquarters of the Cornish marine charity Surfers Against Sewage.
Surfers Against Sewage (SAS) is an environmental charity dedicated to protecting the UK's oceans, waves and beaches. They were established in 1990 by Cornish surfers, campaigning about untreated sewage being drained into the sea and have pressured water companies into cleaning up their act. As well as highlighting any remaining areas for improvement to water treatment, they have also diversified their efforts to tackling other forms of marine pollution, in particular marine rubbish: a plastic bottle left on a beach may persist in the marine environment for more than 450 years, and a large proportion of the rubbish on a beach is sadly dropped there by beach-goers. As well as educating the public, they also organise beach cleans.
Cornwall's iconic engine houses were built to house huge beam engines - a type of steam engine with a pivoting beam. This configuration was particularly suited to powering pumps to stop the quarry pits and mines from flooding as water trickled into them from above. Inside the engine house, steam from a boiler would push up a piston, causing the beam to tilt downwards, pushing the pump down into the shaft. The steam would then be shut off and cold water would be used to condense the steam within the piston back into water, creating a partial vacuum. Atmospheric pressure then pushed the piston back down into the vacuum, raising the beam and lifting water out of the shaft. The valves to apply the steam and cold water were mechanically automated, maintaining a steady rocking motion of the giant beam.
In 1974 Blue Hills Tin was set up as a small-scale tin producer using the tin ore from the seabed that washes ashore at Trevellas Porth. It is dressed and smelted using traditional methods; for example, water-powered stamping machines are used to crush the tin ore. For a number of decades, they have been the only tin producer in the UK, but with tin and copper prices in 2014 around 500% higher than they were in 2000, it's possible that large-scale mining of Cornish tin may once again become economically viable.
Beforehand you can make a short detour to the left to the rocky cove of Trevellas Coombe, returning here to resume the walk. Across the rocks on the left-hand side of the beach is a another small beach with mineral veins in the cliff that contain gold sparkling pyrites crystals.
In rocks on the mine tips or in veins in cliffs above the beaches, you may find golden crystals in the rock. These are likely to either be pyrite (iron sulphide) or chalcopyrite (also containing copper) and are collectively known as "fool's gold". However, there is a little less foolishness involved than the name may suggest:
Trevellas Coombe is a valley close to St Agnes and was known as the Blue Hills due to the colour of the slate here. The place name was first recorded in 1302 as the site of the Trevellas family manor. There is a long history of tin mining in the valley. Initially this was "streaming" for alluvial tin and from the 1690s onward, the stream in the valley provided the power for tin processing. By the late 1800s, almost the entire valley was covered with huge sheds and ore dressing machinery.
Tin is a semi-rare metal well-known for its corrosion resistance which is used extensively in electronics, engineering alloys and anti-corrosion coatings. Unlike many other "heavy" metals, it is not poisonous which has resulted in its use within food packaging - the ubiquitous "tin can" - and increasingly as a replacement for lead, which was used extensively before its toxicity was understood.
Tin is found in Cornwall as the ore cassiterite (tin oxide) which occurs in small crystals amongst other rocks; even a "rich" tin ore only contains 5% tin. The name for the ore is thought either to come from the Greek kassiteros meaning "tin" or from the Phoenician name Cassiterid for Britain and Ireland.
When a bar of tin metal is bent, it emits an audible screaming/cracking sound, known as a "tin cry". This freaky behaviour arises due to a crystallisation phenomenon known as "twinning" that occurs frequently in tin, where two or more crystals grow out of each other, sharing a common section (the name arose from "Siamese twins"). The "crying" sound is caused by these joined crystals snapping apart.
Bluebells are also known by folk names based on their shape including Lady’s Nightcap and Witches’ Thimbles.
Other common names for the bluebell include "wild hyacinth" and "wood hyacinth" as they are related to the hyacinth family. Their Genus name Hyacinthoides also means "hyacinth-like".
At temperatures below 13.2°C, tin slowly changes from a silver-white metal to a grey, crumbly, non-metallic form which causes tin objects to gradually disintegrate at low temperatures. The decomposition catalyses itself, so speeds up once it starts. The transformation, known as tin disease, tin pest, tin blight or even tin leprosy, was first noticed on cathedral organ pipes in the Middle Ages and was assumed to be the work of the devil. As lead is phased out of the solder in electronic items leaving principally tin, this presents a technical challenge as solder which disintegrates all over a circuit board in the cold, only to become conducting again when it warms up, is a recipe for short-circuits.
The "coinage" in the names of some buildings and streets in Cornwall comes from an early method of measuring the purity of metal ore (assaying). Before ingots of tin were sold, a corner of the ingot (known as a "coign") was broken off. The coign was weighed and then reduced with carbon (e.g. anthracite powder) in a furnace and the amount of metal produced was also weighed. The building where the measurement was carried out became known as a Coinage Hall.
In spring, whilst foxgloves seeds are germinating, the established foxglove plants from the previous year start producing their characteristic flower spike. Once these have been fertilised and the seeds have been produced then the plant dies. One foxglove plant can produce over 2 million seeds.
A tax on refined tin was introduced in mediaeval times that was known as Coinage Tax as it was charged based on the purity of tin ore. From 1337-1837, the Cornish tin industry was effectively double-taxed because Cornwall was deemed "foreign". The additional taxation rates levied on Cornish tin compared to that mined in Devon were paid to the Duchy of Cornwall.
On May 15 2000, the Revived Cornish Stannary Parliament sent an invoice to the Duchy of Cornwall for an inflation-adjusted £20 billion for recovery of overcharged taxation on tin production by the Duchy of Cornwall. The invoice, which had terms of 120 days, has so far not been paid. Statutory interest on a late payment of that amount is over £1.5 billion per year.
Spanish bluebells have been planted in gardens and these have hybridised with native bluebells producing fertile seeds. This has produced hybrid swarms around sites of introductions and, since the hybrids are able to thrive in a wider range of environmental conditions, the hybrids are frequently out-competing the native English bluebells. Sir Francis Drake would not be impressed! The Spanish form can be fairly easily recognised by the flowers on either side of the stem. In the English form, they are all on one side. In general, the English bluebells also have longer, less-flared flowers and are often a deeper colour. However, the easiest way to tell the difference between native and non-native bluebells is to look at the colour of the pollen: if it is creamy-white then the bluebell is native; if it is any other colour such as pale green or blue then it's not native.
20 mph speed signs are usually applied alone where traffic speed is already normally slow - e.g. 85% of traffic has been measured at 24mph or less, as a reminder to the remaining 15% of drivers with below-average common sense. Where the average traffic speed is is found to be substantially higher, 20mph zones with traffic calming measures (speed bumps, chicanes etc) are typically used instead.
The original name for the settlement of St Agnes was along the lines of Breanek or Bryanick, a Cornish name which may mean either "Agnes hill", or more mundanely "pointed hill". Either way, this is likely to refer to St Agnes Beacon. Since prehistoric times, the area was a centre for mining copper, tin and arsenic.
At the top of the hill is St Agnes Church.
The first church in St Agnes was believed to have been built in early Celtic times and it also had an enclosure. The current church of St Agnes was built on the same location around 1482. St. Agnes, to whom the church is dedicated, was a Roman girl who was only thirteen years old when she was executed for refusing to marry the emperor's son.
During an excavation in 1931, to add heating to the church, the remains of an earlier chapel were discovered and also a wet area that is thought to be the remains of a holy well. By the churchyard gate is a granite wayside cross which dates from the Middle Ages.
The tiny stream runs for just over a mile from its source near Goonbell to Trevaunance Cove. Over hundreds of millions of years, with the help of a lot of Cornish rain, this has carved the deep valley that St Agnes is perched on.
At the top of the steep hill on your left is a row of cottages known as Stippy Stappy.
The row of 18th century cottages on a steep path from Town Hill in St Agnes known as "Stippy Stappy" was built when St Agnes had a working harbour at Trevaunance Cove. The cottages were built originally for ships' captains, though following the obliteration of the harbour by the sea, their occupancy rapidly diversified.
During Victorian times when the harbour still existed, St Agnes held a regatta. As part of this, local miners would compete in a drilling competition in which a team or two or three men would drill into a piece of granite by hand. Each team had 15 minutes to drill as deep as they could into the rock and the deepest hole would win, which was typically around 2 feet deep. Whilst the Victorians' idea of a good time could not be described as "sex, drugs and rock and roll", given the hardness of granite, this is pretty impressive nonetheless.
Plants such as gorse and heather which are able to grow in soils contaminated with heavy metals such as mine waste tips are known as metallophytes.
There was a concern that if the plants accumulated the metals, whilst themselves being unharmed by them, these might still pass into the food chain e.g. via rabbits eating the plants and then onto buzzards eating rabbits etc.
However, a study of plants from the Carnon Valley found that gorse and heather do not accumulate large quantities of trace metals or arsenic in their tissue. A separate study for a PhD thesis found that for some metals such as zinc, the amount in the plant's tissues (though far lower than in the soil) increased steadily with the levels in the soil. However for certain heavy metals such as lead and copper, the amount measured in gorse tissues appeared to barely increase at all with increasing levels in soil.
Therefore it's thought that there are unlikely to be harmful effects of rabbits eating gorse and heather both directly to the rabbits themselves and indirectly to the food chain of other wildlife.
The Driftwood spars is located beside the road to the beach at St Agnes. The building was converted over the years from a number of buildings dating back to the 17th Century, including a tin mining warehouse, chandlery, sail making loft and fish cellar. The name is derived from the huge timber beams (spars) that are said to have come from ships wrecked along the coast. The pub started its own micro-brewery in 2000 and since then, the beer has won national awards. All the proceeds from their Red Mission beer go to the Cornwall Air Ambulance.
Trevaunance Cove is a shingle beach at high tide and is popular with surfers as its north-facing position means that the prevailing southwesterly winds are offshore. As the tide goes out, the central area of the beach is sandy. To the right, large areas of rock are revealed with numerous rock pools, and at low tide it is possible to clamber over the rocks to reach Trevellas Cove. On the left side of Trevaunance Cove are the remains of the old harbour wall and beyond this there are caves, arches and rock stacks along the cliffs.
Damselflies are predators similar to dragonflies but are easily distinguishable by the way their wings fold back parallel to the body when at rest whereas the dragonflies' wings are fixed at a right angle to the body. The Damselfly has a much smaller body than a dragonfly which means it has less stamina for flight. Nevertheless, it can hover, in a stationary position, long enough to pluck spiders from their webs.
Male damselflies have two sets of genitalia. At the start of mating a packet of sperm (spermatophore) is transferred outside of the male's body between the two and then passed on to the female who uses it to fertilise her eggs as she lays them. Female damselflies lay their eggs inside vegetation. For some species this is in water plants and the female can swim underwater for half an hour before returning to the surface to breathe. Males often guard the egg laying female to prevent a rival male from sneaking in and replacing the spermatophore with his own.
Damselfly eggs hatch not into damselflies but water-living nymphs which look a bit like a dull-coloured damselfly with a 3-forked tail instead of wings. The tail is actually a set of gills used to breath underwater. When the larva is fully developed, it climbs out of the water on a stem or rock. Its skin then splits open and a damselfly emerges with wings which need to be inflated and dry before it can fly.
Common honeysuckle is a native plant also known as woodbine because it wraps itself around other plants and can cause distortions in their growth also called woodbines. Honeysuckle might be regarded as having plant OCD in that it only ever entwines in a clockwise direction.
Honeysuckle flowers appear from June to August and their fragrance is due to a class of chemical compounds known as jasminoids that occur in, as you might have guessed, jasmine but also Ceylon tea. Honeysuckle is the food plant of the White Admiral caterpillar so keep a look for the butterflies in summer.
In autumn, honeysuckle produces shiny red berries that resemble redcurrants. They are toxic to humans and to dogs, but not to birds.
Several species of heather grow in Cornwall and are most easily recognised when they flower from July to September. The one with the most brightly coloured (purple) flowers is known as bell heather due to the bell-shaped flowers. This is the earliest one to start flowering - normally in June. Bell heather is usually interspersed with ling or common heather which has much smaller flowers which are usually paler and pinker and come out at the start of July. A third kind known as cross-leafed heath is less abundant but can be recognised by the pale pink bell-shaped flowers that grow only near the tips of the stems, resembling pink lollipops. A fourth species known as Cornish heath grows only on the Lizard and has more elaborate flowers which are mostly pale with a dark purple crown at the front.
Heathers and heaths are members of the Ericaceae family. The formal definition of a heather is a member of the Calluna genus within this family whereas heaths are members of the Erica genus. Bell heather is actually an Erica and therefore technically not a heather but a heath.
Heather plants have a symbiotic relationship with fungi which grows inside and between some of the plant root cells. Up to 80% of the root structure can be made up of fungi. The fungi are able to extract nutrients from poor, acidic soils that plants struggle with. In return, the plant is able to generate other nutrients (e.g. sugars by photosynthesis) that are useful to the fungi. A similar partnership between plants and fungi occurs in lichens.
Heather can grow in soils which have concentrations of metals normally considered toxic to other plants and they are also tolerant of salty (high sodium) environments on the coast. Their symbiosis with fungi restricts metal uptake through their roots.
Heather plants can live up to 40 years and over time they form woody stems. This provides them with a way of excreting heavy metals that they absorb by locking it up in the layers of dead wood (found by researchers as the areas in the plant with the highest concentrations). Their woody stems have also found many uses over the centuries including fuel, thatch and ropes. One other use has made it into the genus name for heather - kallune is Greek for "to brush".
Mussels are filter feeders and their "foot" is used to generate threads which they use to anchor themselves to rocks. Mussels clump together both to create a more secure attachment to the rock and also to trap water at low tide.
Mussels are preyed on by dog whelks which dissolve a hole in their shell, through which they inject digestive enzymes which result in mussel soup. Mussels have evolved a defensive strategy whereby they lasso invading whelks with their threads and tether them to the rocks, where the whelks starve to death.
Fortunately, consumption of mussels by humans is a little less fraught with danger provided you don't harvest them between May and August: a species of plankton that is poisonous to humans can be hoovered up by the mussels in this period. Make sure you collect more mature mussels of at least 50mm in length as smaller ones are less good to eat. It's worth studying the tides to get the beach for a low spring tide as this is when you'll find the biggest, juiciest mussels. Ideally, take a bucket and bring your mussels home in clean seawater. Once harvested, soak them for a few hours somewhere cool in clean saltwater to allow them to purge any sand (don't submerge them in freshwater as this will kill them). Sort through them, tapping any that are open on a surface to see if they close shut. Discard any that remain open or any that are damaged (they have perished and are not safe to eat). Before cooking, mussels must be thoroughly cleaned and rinsed and the "beard" (threads that secure the mussel to the rock) should be removed.
The frothy "cuckoo spit" that can sometimes be seen on the stems of plants in May and June is a foam produced from plant sap that a froghopper nymph uses to protect itself. This acts as a thermal and moisture-conserving blanket that also hides it from predators and tastes nasty for those that get too inquisitive. The association with cuckoos is simply that it can be seen in spring when cuckoos can be heard.
Froghoppers get their name as the adults jump from plant to plant. Some species can jump up to 70 cm vertically which is even more impressive relative to body weight than fleas. To put this in perspective, on the rollercoaster with the highest g-force in the world, riders experience an acceleration of just over 6 gs. A fighter pilot with a g-suit may experience acceleration of around 9 gs. Froghoppers exceed 400 gs of acceleration and that is self-propelled!
Trevellas Porth is a rocky cove which is pebbly at high tide and as the tide goes out, a large rock platform is revealed and beyond this (on a low spring tide) there is sand. When the tide is out, it's linked by a rock platform to Trevaunance Cove.
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