In tidal rivers, the discharge of freshwater and friction with the riverbed effectively "holds back" the rising tide. The further up the tidal region of the river, the shorter the interval between low and high tide and the faster the rising tide comes in when it eventually does.
The first record of Calstock is in the Domesday Book of 1086 when it had 30 villagers and 30 small farms and encompassed 100 acres of woodland as well as pasture land. The name is Old English (stoc means "dwelling" or "place"), reflecting the Saxon influence stretching into this area of Cornwall before Norman times. The place name expert Craig Weatherhill suggests the original meaning may be along the lines of "outlying farm near a bare hill".
The land on the opposite side of the river is Devon which according to Cornish folklore is where the Devil lives. This is apparently not due to Devon's cream tea heresy but due to the Devil's fear of being used as meat to fill pasties in Cornwall!
"Pasty" was another word used for "pie" throughout England from the Middle Ages onward, and did not necessarily imply the characteristic shape and crimping we associate with the Cornish Pasty. A pasty recipe from 1746 contains no veg, just meat (venison), port wine and spices. The first "Cornish pasty" recipe is from 1861 which contained just beef and no veg.
Even during Victorian times, the main meat available to poor people would have been pork. The Cornish dialect word for a pork flatbread eaten in the mines during the 18th and 19th Centuries is hogen (pronounced "hugg-un") which evolved into "oggy" - the dialect word for pasty. The really poor had a "tiddy oggy" (with no meat at all).
The "traditional" Cornish Pasty recipe contains beef, onion, potato and swede (referred to as "turnip" in the local dialect from its more formal name of "Swedish turnip") seasoned with salt and pepper. It's thought that this probably dates from the late 18th Century (when the Poldark novels were set) when potatoes and turnips were a staple diet for the poor but the first documented "traditional" recipe is not until 1929. Over 120 million Cornish pasties are now consumed each year.
The bridge over Lower Kelly once carried the railway incline leading to Danescombe Quay, built in 1859. It consisted of a 1 in 6 gradient leading to the top of the valley. Wagons were lowered on a rope and raised with the help of a steam engine at the top.
Danescombe House was built in 1856 by the local landowner - Lord Ashburton - and within four years had been renamed the Ashburton Hotel which sought "to remedy Calstock's complete lack of amenities for entertaining visitors". It was soon advertising "water boiled and tea made for parties" and there are stories of visitors coming up the Tamar from Plymouth by paddle steamer for strawberry teas and dancing on the lawn. It was briefly owned by the National Trust who restored the veranda in the 1970s, sold again and then run as a private hotel until the late 1990s.
Buddleia are originally from northwest China and Japan where they grow in forest clearings, on riverbanks and on limestone outcrops where they are able to survive with minimal nutrients. They were introduced into the UK as an ornamental plant in the late 19th Century and can found in many gardens. Some have escaped and established a niche on industrial land which resembles their native limestone outcrops.
The shrub is commonly known as the Butterfly Bush as the flowers are profuse, rich in nectar and are in the shape of champagne flutes; butterflies and bees have sufficiently long drinking apparatus to reach the bottom.
The plant has two types of leaf; the broad green leaves are replaced with shorter hairy grey leaves during the winter which are more resistant to frost and the drying effect of cold winds.
Squirrels are rodents, closely related to chipmunks and slightly more distantly to dormice. The word "squirrel" originates from an ancient Greek word meaning "shadow-tailed", referring to the bushy tail of a squirrel. A family group of squirrels is known as a "drey" (also the word for a squirrel nest). A group of unrelated squirrels is known as a "scurry", though squirrels tend not to hang out in groups.
A railway opened in 1872 to bring minerals from more mines in the area to the Calstock incline leading to the quay. The new railway ran for just over 7 miles to Kelly Bray. At the time, there was no main line nearby so the line was not connected to any other. It wasn't until the early 20th Century that the new railway in Plymouth allowed the Calstock railway to be connected, and much of the trackbed of the East Cornwall Mineral Railway was re-used for the Tamar Valley line.
The bridge crossed an inclined plane of the original East Cornwall Mineral Railway that was abandoned in 1908 when the rest of the mineral railway was re-purposed as part of the Plymouth, Devonport and South Western Junction Railway.
Rhododendron is a member of the Ericaceae family to which heathers also belong and like its cousins, it is tolerant of acid soils. The word rhododendron is from the Ancient Greek for "rose tree" due to their spectacular flowers. As a result of these, rhododendrons have been popular ornamental plants for over two centuries and the species that we now call the common rhododendron was introduced in 1763. The plants thrive in the UK climate and were once native but were wiped out by the last Ice Age. Being a vigorous plant, common rhododendron was often used as a root stock onto which more fragile but exotically-coloured hybrids were grafted.
Cotehele and Calstock lie within the Tamar Valley AONB.
The Tamar Valley Area of Outstanding Natural Beauty has a similar conservation status to a National Park. It encompasses an area of 75 square miles around the rivers Tamar, Tavy and Lynher, partly in Cornwall and partly in Devon. This also includes an area of Cornwall and West Devon mining landscape World Heritage Site, 41 county wildlife sites and over 1700 hectares of woodland. It was first suggested in 1963 that the Tamar valley area should be designated but this was only eventually granted in 1995.
In 2006-7 a team from Exeter University were doing surveys to investigate mediaeval silver mines when they accidentally discovered a Roman Fort. This is only the third one found in Cornwall and is the largest. It is thought to have been in use from the 1st Century AD. It was enclosed by two ramparts and ditches and finds have included remnants of furnace-lining, ore and slag which indicate metalworking was taking place. For a long time there was a suspicion that there might have been a Roman military interest in Cornwall's mineral resources and this is some of the first evidence that supports this.
Calstock church was consecrated in 1290, is dedicated to St Andrew and is under the Patronage of The Duke of Cornwall. The current building dates from the 15th Century and includes a mediaeval wall painting which was rediscovered during a Victorian restoration. The porch includes a built-in fireplace, the purpose of which is not definitely known but it is thought that this was believed to keep disease out of the church, along the lines of "keep warm or you'll catch a cold".
The Vikings used crushed conkers to make soap as they contain saponins. As fresh conkers dry out, the saponins are released and scientists have found these repel moths. However no evidence has been found that they repel spiders despite many people believing this to be the case.
The section of the railway across the Calstock viaduct from Bere Alston was built in the 1900s just as the surveying was taking place for the 2nd edition of the OS map. Consequently various sections of the half-built railway are recorded on the map as "Railway in the course of construction" and the viaduct was just a series of pillars at this point. The new railway joined the existing East Cornwall Mineral Railway at Albaston (between Calstock and Gunnislake station) and the new station at Calstock opened in 1908. This created a railway line all the way from Plymouth to Kelly Bray. The section from Kelly Bray to Gunnislake was eventually closed but the remainder survives as the Tamar Valley Line.
Okel Tor mine operated between 1849 and 1887 and extracted primarily copper and arsenic. Tin and lead ore (which also contained silver) were also extracted. In 1865, it was recorded as having two engines and employing 107 people: 80 men, 15 boys and 12 bal maidens.
The name Tamar is documented in the second century and likely to be substantially older. It is thought it might share a common origin with the River Thames and both might stem from an ancient Celtic word meaning "dark". The source of the river is within 4 miles of the North Cornish Coast and the river flows 61 miles south across the peninsula forming the majority of the historic border with Devon. Work is being done by the Environment Agency to improve the water quality of the Tamar and its tributaries by reducing the amount of run-off of phosphate fertilisers into the rivers.
The Calstock viaduct is part of the Tamar Valley railway that was constructed at the start of the 20th Century and still runs between Gunnislake and Plymouth. The viaduct was built between 1904 and 1907 from 11,148 precast concrete blocks. It is 120 feet high with twelve main arches each 60 feet wide, and one mini-arch at the Calstock end. Originally, a steam-powered lift was attached to it which could raise and lower wagons from the quays over 100 feet below.
The Tamar Discovery Trail was created in the early 21st Century after Tamar Valley AONB was established. The 35 mile route - partly in Cornwall and partly in Devon - was originally indicated by waymarks with an apple symbol which is a reference to the area's horticultural heritage. It was known affectionately as the "apple trail" and some of these are still visible, inscribed into the wooden posts. More recently, waymark arrows with a bee (based on a new logo for Tamar Valley tourism) have been added to the route.
Some estimates suggest the UK has up to half of the world's total bluebell population; nowhere else in the world do they grow in such abundance. However, the poor bluebell faces a number of threats including climate change and hybridisation from garden plants. In the past, there has also been large-scale unsustainable removal of bulbs for sale although it is now a criminal offence to remove the bulbs of wild bluebells with a fine up to £5,000 per bulb!
During periods of cold weather, spring flowers, such as bluebells, have already started the process of growth by preparing leaves and flowers in underground bulbs during summer and autumn. They are then able to grow in the cold of winter, or early spring, by using these resources stored in their bulb. Once they have flowered, the leaves die off and the cycle begins again.
Other species (such as cow parsley or dandelions) require warm weather before they are able to germinate and grow. With the warmer springs induced by climate change, bluebells lose their "early start" advantage, and can be out-competed.
Because bluebells spread very slowly, they're considered to be an indicator of ancient woodland sites. In areas where trees are not very old, the fact there are bluebells around can indicate that there has been a wood on a site for a very long time. Even if there are no trees there at all, bluebells tell us that there was woodland there some time in the past. The bluebells along the coast are a relic of the gnarled oak woodland that used to grow here before it was cleared for grazing. There is still a patch of the ancient oak woodland left along the coast at Dizzard.
Some plant nutrients such as phosphorus tend to be more abundant near the surface of the soil where decaying organic matter collects. Bluebell seedlings start life at the surface so these are OK but as bluebell plants mature and send their roots deeper into the soil to avoid winter frosts, they have a phosphorus problem. They have solved this by partnering with a fungus that extends from their root cells, drawing in minerals from the soil in return for some carbohydrates from the plant.
Bluebells are extremely poisonous, containing a number of biologically-active compounds and were used (probably with varying success) in mediaeval medicine. The sap was used as a glue for book-binding as its toxicity repelled insects. It was also used to attach the fletchings onto arrows.
In Elizabethan times, starch made from the bulbs was used to stiffen collars and cuffs in clothing. The ruffs that were highly fashionable at the time would have needed a lot of starch to prevent them flopping. The toxins in bluebell sap might also have had the desirable property of preventing the starch encouraging the formation of mould.
In folklore, the bluebell is a symbol of constancy, presumably based on the fact that they flower in the same place every year. It was said that anyone who wears a bluebell is compelled to tell the truth. This could be the origin of the "…something blue…" that a bride should wear on her wedding day.
According to folklore, it's unlucky to bring bluebells into a house and also unlucky to walk through bluebells as it was thought that the little bells would ring and summon fairies and goblins.
In Old Cornish, both bluebells and marigolds were known as lesengoc which translates to "flower of the cuckoo". In Modern Cornish, the marigold has remained more-or-less the same but the bluebell has been changed to bleujenn an gog ("plant of the cuckoo"). The association between bluebells and cuckoos exists in Welsh ("bells of the cuckoo") and Gaelic ("cuckoo's shoe"), and in some English folk names such as Cuckoo's Boots and Cuckoo Stockings. It is thought that the association is due to the time that bluebells flower coinciding with the time that the call of the cuckoo is first heard.
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".
When photographing bluebells, the flowers that look blue to your eye can end up looking purple in photos.
The first thing to check is that your camera isn't on auto white balance as the large amount of blue will cause the camera to shift the white balance towards reds to try to compensate.
Another thing to watch out for is that the camera's light metering will often over-expose the blue slightly to get a reasonable amount of red and green light and the "lost blue" can change the balance of the colours. You can get around this by deliberately under-exposing the photo (and checking there is no clipping if your camera has a histogram display) and then brightening it afterwards with editing software.
Bluebells are very vulnerable to trampling. The reason for this is that when their leaves emerge in the early part of the year, they are powered by the stored sugars in their bulbs. Sunlight is very limited at this time of the year and even more so in the shady places where they grow. In order to survive, they then need to photosynthesise flat-out to store enough starch in the bulb for next year's growth. If a bluebell’s leaves are crushed, it cannot photosynthesise and and doesn't have enough reserves left in its bulb to grow new ones. It's therefore important to stick to footpaths in bluebell woodland and best to take photos with a zoom lens from there as wandering around in the bluebells to take photos will inadvertently kill them.
A rare genetic mutation occurs in bluebells which results in about 1 bluebell in 10,000 being white rather than blue.
Three-cornered leeks - which have white bell-shaped flowers and are very common - are often misidentified as "white bluebells". The easiest way to tell them apart is that 3-cornered leeks smell strongly of onion. Their flower stems are also triangular (hence the name).
We are so used to seeing sediment in rivers that we've come to accept it as normal but no river should be brown. Sediment is often a product of human activity including eroded river banks, runoff from ploughed farmland and even cattle poaching. It can smother riverbed gravels that are essential for fish spawning. It can also act as a carrier for other pollutants such as heavy metals and pesticides. As well as being toxic, the smell of these chemicals can prevent salmon from detecting their home spawning grounds. That may all sound a bit doom and gloom but the good news is that this damage can be reversed. Pilot schemes of washing and returning gravel to the rivers have had spectacularly promising results, with breeding salmon becoming re-established within just a few years. The Westcountry Rivers Trust are also working with farmers on improving drainage systems to steadily reduce the amount of new sediment and chemicals entering rivers.
In America, during the 1870s, Colorado beetle was devastating cash crops including cotton, tobacco and staples such as potato. At the time, the most popular pesticides were arsenic compounds so this led to a sudden increase in demand for arsenic. Since this was soon after the collapse in copper prices, this delayed the closure of many mines and during this period, over half of the world’s supply of arsenic was produced from mines in Cornwall and Devon.
Arsenic is a chemical element that is part-way between a metal and non-metal, known as a metalloid. In the natural environment it reacts with oxygen to form an oxide which readily dissolves in water to form arsenic acid. This is able to leech into groundwater and cause contamination. Deeper in the ground where sulphur is more available than oxygen, arsenic is found as sulphide compounds.
The name arsenic is ultimately from Arabic al-zarnīḵ where the "zar" element is a Persian word for "gold" (as an arsenic sulphide compound known as "orpiment" was used as a yellow pigment).
Arsenic disrupts the production of the ATP (energy carrying) molecules vital in the metabolism of multi-cell organisms (in plants as well as animals). Due to its toxicity, arsenic was used as an insecticide and rat poison, and by the ruling class to murder one another. As the toxicity extends to plants, highly contaminated ground often has limited or stunted vegetation.
Arsenic had a variety of chemical uses including metal alloys, clarifying glass and in pigments. In Victorian times, an arsenic-based pigment known as "Scheele's Green" (copper arsenate) was used to colour sweets green. Later, the same compound was used as an insecticide!
Arsenic pigments were also popular in Victorian wallpaper manufacture to create green and yellow print. Unfortunately in the Industrial Revolution smogs, these arsenic compounds reacted with the acidic coal fumes to form lethal arsine gas which is even more toxic than arsenic itself.
During Victorian times, having a sun tan was seen as common, as peasants working in the fields were out in the sunshine. In order to make their faces paler, women of the higher social classes rubbed arsenic into their faces and arms. They also mixed arsenic oxide with vinegar and chalk and ate this! The Victorian notion that women were "frail creatures" would certainly have been helped along by eating arsenic.
Deep in the earth's crust where there is lots of sulphur and little oxygen (hence the smelly sulphur compounds around volcanic vents), copper occurs as crystals of sulphide compounds. Nearer the surface, chemical reactions with air and water form brick-red oxide and blue-green carbonate compounds and also copper sulphate. The latter is the blue stuff from school science lessons which you may vaguely recall is soluble in water; thus it became concentrated at the water table. In the Ice Ages that followed, Cornwall was scoured by glaciers which bulldozed away many of these concentrated deposits. Early copper mining took place on the few remaining areas of these surface layers, but it was not until innovations in pumping technology that copper mining could be carried out on the deeper sulphide deposits and these account for the bulk of the ore mined. The most common ore (called chalcopyrite) is a copper-bearing version of "fool's gold"; when pure it looks like gold but where it meets air and water, patches of iridescent green, blue and purple form and so it was known as "peacock copper".
The commonest copper ore - chalcopyrite - is often hard and brittle with a tendency to break into a very fine powder. Tin mines were operated by mechanically crushing all the rocks and then concentrating the granules of ore through a series of processes using water. However, with copper, this would have led to large amounts of fine ore particles being lost as waste so instead as much of the processing as possible was done by hand, leaving mechanical stamping for only the hardest of rocks.
By Victorian times, the parish of Calstock had more lime kilns than any other in Cornwall, with many of these along the river at Lower Kelly and Cotehele where coal and limestone were landed. Often culm (a local soft, peaty coal) was used as the fuel. The coal and limestone was loaded into the top of the kilns and was allowed to burn for a week; this produced quicklime which was raked out of the bottom. The lime from the kilns was transported by horse and cart to the nearby farms and market gardens.
Biologically, there is no clear distinction between ducks, geese and swans (geese and swans are one lanky subfamily of ducks). Dark-coloured ducks get the equivalent of "grey hairs" with age - their feathers gradually turn white.
The species of duck that you're most likely to encounter is the mallard. Mature males have striking iridescent green heads and dark bodies whilst females look totally different - a brown and white pattern which offers much better camouflage. However, both have a common feature that is unique to mallards - an iridescent blue patch on their wings.
In situations where ducks need to watch out for predators, they can sleep one half of their brain at a time, keeping one eye open for danger. In safer circumstances, ducks will sleep fully.
Male ducks (drakes) have a penis which falls off every autumn and regrows the following spring. The length each year depends on the amount of competition for females and varies up to a maximum of the duck's whole body length.
Ducks can change gender. This happens for about 1 duck in 10,000 and more commonly from female to male than the other way around. It seems to occur in a flock of ducks where there is a significant gender imbalance where it gives the duck that changes a competitive advantage. It's likely that the female to male direction is a bigger evolutionary win because one male can fertilise multiple females.
Feeding bread to ducks is quite bad for them although not feeding ducks anything at all is potentially worse as many have now become reliant on being fed. White bread lacks many of the nutrients that ducks need but ducks will gorge on it to the point of ignoring other foods, effectively becoming junk food addicts. The problem is that by filling up on just this, they can become malnourished, deformed and even die. Some healthier things to feed ducks are leftover peas, sweetcorn, seeds, rice and salad.
Purple loosestrife usually grows in damp places such as next to a stream and can be spotted from spikes of bright purple flowers in August-September.
The common name is thought to be the result of a 16th century mistranslation of the Latin name. Attempts were then made to make "loose strife" fit with reported uses for the plant to try to rationalise the wacky name. The Latin name is now thought simply to refer to the name of city in Thrace (Greek-Turkish border) which perhaps had the plant growing along its watercourses.
The Red Admiral, Peacock, Painted Lady and Tortoiseshell butterflies are all quite closely related and specialised for overwinter hibernation. Their wings, when closed, have a jagged outline and camouflaged colours that allows them to blend in with dead leaves. Their feet contain chemoreceptors (taste buds) which allows them to detect nectar-bearing flowers when they land.
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