Mendip Hills

The Mendip Hills is a range of limestone hills to the south of Bristol and Bath in Somerset, England. Running from Weston-super-Mare and the Bristol Channel in the west to the Frome valley in the east, the hills overlook the Somerset Levels to the south and the Chew Valley and other tributaries of the Avon to the north. The highest point, at above sea level, is Beacon Batch which is the summit area atop Black Down. The hills gave their name to the former local government district of Mendip, which administered most of the local area until April 2023. The higher, western part of the hills, covering has been designated an Area of Outstanding Natural Beauty, which gives it a level of protection comparable to a national park.
The hills are largely formed from Carboniferous Limestone, which is quarried at several sites. Ash–maple woodland, calcareous grassland and mesotrophic grassland which can be found across the Mendip Hills provide nationally important semi-natural habitats. With their temperate climate these support a range of flora and fauna including birds, butterflies and small mammals. The dry stone walls that divide the pasture into fields are of botanical importance as they support important populations of the nationally scarce wall whitlowgrass.
Mendip has seen human activity since Palaeolithic and Mesolithic times with a range of artefacts being recovered from caves. Neolithic, Iron Age, and Bronze Age features such as barrows are numerous with over 200 scheduled ancient monuments recorded. There is evidence of mining in the Mendips dating back to the late Bronze Age, which increased after the Roman invasion, particularly for lead and silver around Charterhouse. The difficult conditions in the area were noted by William Wilberforce in 1789, which inspired Hannah More to begin her work improving the conditions of the Mendip miners and agricultural workers. In the 18th and early 19th centuries of the common heathland on the hills were enclosed. In World War II a bombing decoy was constructed on top of Black Down at Beacon Batch. More recently, the mast of the Mendip transmitting station, micro-hydroelectric turbines and a wind turbine have been installed.
There are several quarries on the Mendip Hills. Some of the stone is still carried by Mendip Rail; the other railways in the area closed in the 1960s. Although the Roman Fosse Way crossed the hills, the main roads generally avoid the higher areas and run along the bottom of the scarp slope on the north and south of the hills. The western end of the hills is crossed by the M5 motorway and A38. Further east, and running almost north to south, are the A37 and A39. A wide range of outdoor sports and leisure activities take place in the Mendips, many based on the particular geology of the area. The hills are recognised as a national centre for caving and cave diving, as well as being popular with climbers, hillwalkers and natural historians. Wookey Hole Caves and some of the caves in Cheddar Gorge are open as show caves; however, many of the caves of the Mendip Hills are only accessible to members of caving clubs. Long-distance footpaths include the Mendip Way and Limestone Link.

Toponymy

There has been a great deal of debate, over the course of decades if not centuries, about the provenance and meaning of the toponym 'Mendip', and as late as 2000, two leading place-name scholars felt able to remark that "Mendip is probably best regarded as unsolved". However, an idea put forward in a 1986 paper, by one of the UK's leading academic place-name researchers, seems to have regrettably fallen beneath the radar, and has not had the widespread currency that it deserves. The author of the article was Richard Coates, now Emeritus Professor of Linguistics at the University of the West of England. Following a review of earlier evidence, Prof. Coates suggested that Mendip is a hybrid name, part British and part Old English. He posits a first element mönïð, from Primitive Welsh, meaning 'a hill', and Old English yppe, 'a hunting dais'. The strong sense of the word in its entirety is 'an upland area used for hunting'. The logic and elegance of this explanation is extremely clear - the Mendip plateau had been used explicitly as a hunting ground by the Anglo-Saxon kings, something strikingly reinforced by the story of King Edmund, in the middle of the 10th century, escaping death by a whisker as the stag he was chasing plunged to its death over Cheddar Gorge, his own horse only pulling up short at the last minute on the very lip of the cliff. The Normans placed Mendip under Forest Law for the same reason.

Geology

The rock strata known as the Carboniferous Limestone were laid down during the early Carboniferous Period, about 320–350 million years ago. Subsequently, much of northwestern Europe underwent continental collision throughout the late Paleozoic Era, culminating in the final phases of the Variscan orogeny near the end of the Carboniferous, 300 million years ago. This tectonic activity produced a complex suite of mountain and hill ranges across what is now southern Ireland, south-western England, Brittany, and elsewhere in western Europe.
File:JurRockgd01.jpg|thumb|alt=Brown and yellow image with oval and long thin areas representing the fossilised remains|left|Cross-section of a Carboniferous Limestone bored by Jurassic organisms; borings include Gastrochaenolites and Trypanites; Mendip Hills; scale bar = 1 cm
As a result of the Variscan mountain-building, the Mendip area now comprises at least four anticlinal fold structures, with an east–west trend, each with a core of older Devonian sandstone and Silurian volcanic rocks. The latter are quarried for use in road construction and as a concrete aggregate. The Mendips were considerably higher and steeper 200 to 300 million years ago, and subsequent erosion has resulted in varying geological features including gorges, dry valleys, screes, swallets and others typical of karst landscapes. Beneath the southern escarpment and plateau are caves. There are also areas of limestone pavement and other karst features. Dissolution of the limestone produced many of the gorges including Cheddar Gorge and Burrington Combe. Springs are a common feature of the eastern part of the hills, a number of which have associated tufa deposits.
Black Down is a moorland area, with its steeper slopes covered in bracken and its flatter summit in heather and grasses rather than the pasture which covers much of the plateau. The main body of the range is an extended plateau, wide and generally about above sea level.
In some places lead and zinc ores have mineralised the limestone and the dolomitic conglomerate. From the time of Roman Britain until 1908, the hills were an important source of lead. These areas were the centre of a major mining industry in the past and this is reflected in areas of contaminated rough ground known locally as "gruffy". The word "gruffy" is thought to derive from the grooves that were formed where the lead ore was extracted from veins near the surface. Other commodities obtained included calamine, manganese, iron, copper and baryte. The eastern area reaches into parts of the Somerset Coalfield.
North and east of the Mendips the Carboniferous Limestone layers are found in the subsurface and are exposed in Avon Gorge, and are overlain by younger strata in Dundry Hill and the Cotswolds, where oolitic limestone of Jurassic age is found at the surface. West of the main Mendip plateau the Carboniferous Limestone continues in Bleadon Hill and Brean Down, and on the islands of Steep Holm and Flat Holm in the Bristol Channel.
The hills gave their name to the rare mineral mendipite, an oxohalide of lead with chlorine with formula Pb₃Cl₂O₂ which was first described in the area. A sample of mendipite was found at the head of Ebbor Gorge.

Climate

Along with the rest of South West England, the Mendip Hills have a temperate climate that is generally wetter and milder than the rest of England. The annual mean temperature is about with seasonal and diurnal variations, but the modifying effect of the sea restricts the range to less than that in most other parts of the United Kingdom. January is the coldest month, with mean minimum temperatures between. July and August are the warmest, with mean daily maxima around. In general, December is the dullest month and June the sunniest. The south-west of England enjoys a favoured location, particularly in summer, when the Azores High extends its influence north-eastwards towards the UK.
Cumulus cloud often forms inland, especially near hills, and reduces exposure to sunshine. The average annual sunshine is about 1,600 hours. Rainfall tends to be associated with Atlantic depressions or with convection. In summer, convection caused by solar surface heating sometimes forms shower clouds, and a large proportion of the annual precipitation falls from showers and thunderstorms at this time of year. Average rainfall is around. About 8–15 days of snowfall is typical. November to March have the highest mean wind speeds, with June to August having the lightest; the prevailing wind direction is from the south-west.
A combination of the rainfall and geology leads to an estimated average daily runoff from springs and boreholes of some 330,000 m³. Bristol Waterworks Company recognised the value of this resource and between 1846 and 1853 created a series of tunnels, pipes, and aqueducts called the "Line of Works", which still carry approximately 18,200 m³ of water a day to Barrow Gurney Reservoirs for filtration and then on to Bristol and the surrounding areas. This collection and conveyance of water from the Chewton Mendip and East and West Harptree areas is accomplished by the effect of gravity on the runoff. Water from the Mendips is also collected in Cheddar Reservoir, which was constructed in the 1930s and takes water from the springs in Cheddar Gorge.