Walking on Dartmoor. Earle John
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Название: Walking on Dartmoor
Автор: Earle John
Издательство: Ingram
Жанр: Книги о Путешествиях
isbn: 9781849655118
isbn:
Meldon Reservior
Blacktor Falls, River Meavy
The rolling, sweeping horizon of Dartmoor with its huge skies always thrills me. Except for a few steep-sided valleys you are never shut in on the moor; you always have the feeling of distance and vast open spaces. Everywhere, except in prolonged summer drought, there is the presence of water; quaking bogs, small streams and the peaty, moorland rivers tumbling down over water-rounded granite boulders, while high overhead the skylarks pour out their own evocative liquid song.
Of course a lot of the landscape, certainly on the margins but also in some of the remote river valleys, where the tinners have been at work, has been fashioned and changed by man. Man has lived, hunted and worked on Dartmoor since prehistoric times and obviously has left his mark, from hut circles, stone rows and megaliths, to tinners’ spoil tips and blowing houses, to newtakes, peat cuttings and ancient fields, to china clay works, forestry and dams.
I find this history of man on Dartmoor, especially the prehistoric period, fascinating. I still feel a strange, prickling sensation in the scalp when I am alone in one of the areas of hut circles or stone rows. Almost I sense the spirits of the Bronze Age people of 4000 years ago. It is no wonder that Dartmoor has its share of legend and folklore and up in the deep peat hags of Cut Hill you could almost believe in the stories of pixies!
Sadly there are very few of the true, old Dartmoor farmers and their families left in our modern times. Men and women for whom a trip to Exeter or Plymouth was a once-a-year outing, who thought nothing of travelling to market in gig or cart, taking two or three hours there, and back again, whose slow, hard life revolved around the seasons and the harsh taskmaster Dartmoor.
Life and the old ways have changed from the days when every small village had its bakery and blacksmith, when the grocer, the butcher, even the fishmonger from Brixham, the haberdasher and tailor delivered to the door of remote farms by pony trap; when harvest suppers and whortleberry gathering parties were part of the year's major social events. Modern farmers on Dartmoor are a different breed, but just here and there are a few folk whose memories reach back into the old days and the ways of their fathers and grandfathers before them.
The wildlife on Dartmoor is not outstanding but when you do come in contact with the secret inhabitants, it is the more exciting. The buzzard, I suppose, with its moth-like wings and the mewing call, like a kitten, is the most common big bird on the margins of the moor and in many way epitomises Dartmoor with its soaring, wheeling freedom or sitting like a sentinel on a pole or bare tree surveying the world. Then there is the thrill as a couple of red grouse get up with a clatter and their loud ‘go back’ call, or the excitement or the brief glimpse of a reddy-black, arrogant hill fox loping off in no hurry. But it is the skylark, that minute speck in the blue summer sky, with its bubbling song, that brings back a surge of happy, childhood memories of walking or riding on hot, breathless days into the heart of the moor and I still scan the skies trying to find the little, soaring creature pouring out its ecstasy.
The Nine Stones lookng back to Cullever Steps with High Willhays beyond, Walk 34
I hope therefore to share with you, through this Guide, some of the magic and mystery of Dartmoor. I should like to show you places to visit that I think will interest and fascinate you, so that like me, you will become a person who loves and appreciates this lonely wilderness and will return to it again and again, for it has a haunting, almost hypnotic influence on those who walk there.
Geology and formation of Dartmoor
This Guide is no place to give a full and detailed description of the geology of Dartmoor. For those who would like more information, it can be found in some of the excellent books listed in the bibliography. However to appreciate and understand the moor and its landscape, it is interesting at least to know how Dartmoor was formed and something of what happened over the millennia since its creation.
At a time when the Earth began to look green as plants and even small trees evolved and the seas were full of vertebrate animals such as primitive sharks that eventually led to the existence of the first amphibians, where Devon and Cornwall are now was part of a huge flooded plain. The sediments of certain areas of this plain became the early rocks seen now, such as the Dartmouth slates and Devonian limestone. This time in the development of the Earth was known as the Devonian period and occurred 400 million years ago and lasted some 50 million years.
As the warm seas encroached the southern areas of what was to become the British Isles changes took place. Coral reefs grew in the seas and volcanoes erupted here and there. Sediments, mud and sand, accumulated round the coral reefs and volcanic debris and we have the beginning of the Carboniferous period, 345 million years ago, which overlapped with the previous Devonian period. It was, of course, the chief coal forming age associated with the coal seams and carboniferous limestone.
Then as this period came to an end, about 290 million years ago, both the Carboniferous and Devonian deposits were subjected to mountain building pressures and foldings known as the Armorican movements. The rocks and soils of Devon and Cornwall as we know them now were formed at this time. The limestones and sandstones appeared, caused by the great folds and upthrusts.
It was about this time too, 290 million years ago, that the granite of Dartmoor probably arrived from below the earth's crust, though dating such events is fairly difficult. Granite is an igneous (Latin: fiery) rock and is formed under conditions of intense heat. Dartmoor granite arrived as an igneous intrusion into those overlying sedimentary rocks which, because of the violent folding they had been subjected to, had many faults and cracks. Some of the granite was able to follow these weaknesses to the surface while in other areas the granite welled up under the Devonian and Carboniferous rocks like water in a blister. Some of the sedimentary rock even became absorbed into the granite itself because of the ferocious heat. So we have the characteristic dome-shaped mass of rock, in an area some 365 square miles, in the centre of Devon.
Because the granite was protected by the layers of rock above from the cold air, the molten rock cooled very slowly resulting in large visible crystals; the slower the cooling process, the larger the crystals. Gradually the protective layer was eroded and destroyed by the weather during the Permian period and in time the granite boss was exposed.
Scorhill Circle, Walk 33
Later during the millions of years that followed a layer of granite itself between 50m and 200m (150–650ft) thick was also eroded, until we have Dartmoor as we know it today.
Dartmoor granite is composed mainly of three types of crystal. First quartz, which is the glassy grey substance that in its pure form produces the distinctive six-sided crystals with pyramidical points and striations on the sides. Next the small dark, glistening specks of black mica, a crystal that occurs in many of the massive rocks, and lastly felspar, which gives granite its colour: red, white or grey. These are the larger crystals seen in granite. It is felspar, when it has decayed or been decomposing by weathering, that becomes kaolin or china clay.
For several different reasons there are many varieties of granite to be found on Dartmoor.
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