Natural History in the Highlands and Islands. F. Darling Fraser

Чтение книги онлайн.

Читать онлайн книгу Natural History in the Highlands and Islands - F. Darling Fraser страница 9

Natural History in the Highlands and Islands - F. Darling Fraser

Скачать книгу

The snow lies long up here but in summer there is a wealth of excellent grazing for deer, sheep and cattle. I have found patches of beautiful brown soil as high as 1,800 feet. One of the best routes into the Cairngorms is up Glen Tilt from Blair Atholl, past the Falls of Tarf. It is a long and arduous defile or U-shaped glacial valley for most of the way until the Bynack Shieling is reached at 1,500 feet. After that there is the sense of height and space, and the high hills of the Cairngorms lie ahead in a much more picturesque group than when seen from the west. This time it is the noble Glen Dee which splits the massif rather than the sharp nick of the Lairig Ghru. Trees are few up here, though the narrow dens which cut down to the Tarf from Fealar and round about have plenty of small birches, and curiously enough there are a few well-grown spruces at the Bynack Shieling; out of which spruces one day I frightened a capercaillie (Plate XIc). He must have come out of the wooded area of the Dee below Derry Lodge, where this bird is relatively common. The Forest of Mar was one of the places where the caper was reintroduced (unsuccessfully) in the early 19th century.

      THE NORTHERN HIGHLANDS, A ZONE OF SUB-ARCTIC AFFINITIES

      The northern end of Drum Albyn and its coasts becomes definitely a harder country north of Loch Carron than the West Highland Atlantic zone. The large island of Skye, set athwart the Minch, has an undoubted effect of checking the flow of warm water of the North Atlantic Drift. The coasts of the North-West have several long sea lochs, but the coast as a whole is tighter-knit than the islands and coasts of the Atlantic zone which fans out from the Firth of Lorne into the Atlantic Ocean.

      The rocks of the northern zone on the western side are mostly very hard, and poor in such minerals as make good soil; they are Lewisian gneiss, Torridonian sandstone and quartzite; these three have little either of calcium or of fine particles which will become clay and contribute to the soil picture. Furthermore, where the bed rock itself is not showing through (and often it is over 50 per cent of the landscape) the ground is covered with peat which has no bottom of shell sand or clay which, on disintegration or removal of the peat, might become productive soil. Sand dunes occur on the coast at only a few places such as Gairloch, Gruinard Bay, Achnahaird on the north coast of the Coigach peninsula, across Rhu Stoer and at Achmelvich, and at Sandwood Bay a few miles south of Cape Wrath. None of these are of shell sand.

      It is a hard, rocky coast to which a multitude of short, rapid rivers run from Drum Albyn—the Laxford from Loch Stack and Loch Mor into Loch Laxford; the Inver from Loch Assynt into Enard Bay; the Kirkaig out of the lochs below Suilven; the Polly, the Kannaird, the Broom and the Dundonnell Rivers; the superb Gruinard River which is only six miles long on its run from Loch na Sheallag; the Little Gruinard, even shorter, coming from the Fionn Loch which is one of the most famous trout lochs in the North; and the River Ewe, only two miles long after it leaves Loch Maree, but very broad; the Kerry River running into Gairloch, famed for its pearls; and the Applecross River which drains much of the peninsula of that name. Most of these rivers are noted for salmon and sea trout, though some are curiously poor. As things stand at the moment the rivers of this region, so variable in their flow from day to day, make up in economic value for the poverty of the land for agricultural and pastoral purposes and for general lack of timber.

      The boreal or sub-arctic affinities of the northern zone are most marked on the two geological formations already named, the gneiss and the sandstone. Each rock has its very distinctive form and each contributes to what is probably the wildest scenery in Scotland except for the small area of the Cuillin Hills of Skye (Plate IIIa). But here in the interplay of gneiss, sandstone and quartzite the naturalist may walk for a week or more and see no human habitation other than an occasional stalker’s cottage. So rough and wild is the country that habitations unconnected with sport are difficult to find away from the sea’s edge. The outcrop of limestone in the Assynt district allows the exception of the crofting townships of Elphin and Cnockan to which allusion was made in the first chapter.

      The Lewisian gneiss of the mainland rises to greater heights in the general run of the country than it does in the Hebrides, except in Harris and at one place in South Uist. Also, it is not hidden under such a blanket of peat as in Lewis. The gneiss country of Sutherland and Ross is one of a myriad little hills of great steepness, with little glens running hither and thither among them. The lochans are seemingly countless and most of them have a floor of peat. The gneiss hills themselves are like rock buns, looking as if they had risen in some giant oven and set into their rough shapes. This ground holds up the water in pockets in the rock and allows the formation of cotton sedge bogs and such very shallow lochans as grow water lobelia and water lilies. When these lochans are near the sea and grow reeds the bird life is rich. Greenshanks (Plate XIIb) are common in the gneiss country—say one pair to 3,000 acres, which is quite twice as many as may be found on the adjoining Torridonian sandstone. Heather (Calluna) is not common on the gneiss; the complex is one of dwarf willow, sedge and poor grasses. Also, this type of vegetation does not appreciably alter in the altitudinal range of the gneiss. For example, I could find no major difference in sample patches in the Gruinard Forest at the foot of Carn nam Buailtean at 600 feet, and at the top of Creag Mheall Mor in the Fisherfield Forest at over 2,000 feet. The hills maintain over all their mottled pattern of green and grey, and when the snow is on the tops there is never the distinctive line at about 1,750 feet which is commonly seen on the Torridonian formation.

      The gneiss is difficult country to walk through: by keeping to the little glens it is impossible to steer a straight course for any distance and no one would attempt to go in a straight line over the hills. On the upper gneiss country where many detours are necessary round rock faces and soft spots, a speed of one mile an hour is quite good going. It is also quite easy to lose one’s self, for these little round hills are all very much alike.

      The crofting townships on the gneiss are strictly coastal. Their arable grounds (Plate 7b) are usually tiny patches of an acre or less in the hollows or in the less steep faces of the rocks. Loch Laxford, a sea loch, shows some typical low gneiss country with crofts at Foindlemore and Fanagmore.

      The gneiss tends to get higher the farther it goes inland. A’ Mhaighdean (the maiden) reaches 2,850 feet above the Dubh Loch in Ross, 10–12 miles from the sea as the crow flies. It forms a high cliff face on this hill of exceptional grandeur, a rare thing for the formation on the mainland. Its sea cliffs are nowhere impressive here because they are never sheer or higher than a couple of hundred feet. Even the Torridonian, a formation which one might expect to make magnificent cliffs, does not provide these in any quantity at the sea’s edge. The island of Handa, near Scourie and opposite Fanagmore at the mouth of Loch Laxford, is a splendid exception. The Torridonian rock is stratified horizontally, so the vertical breaks make nesting ledges for sea birds such as guillemots, razorbills and kittiwakes. There are sheer cliffs of nearly 400 feet on Handa, and in the little screes of earth among these, now covered with fescue and scurvy grass, there are large colonies of puffins and fulmar petrels. The white-tailed sea eagle nested on Handa until the second half of the 19th century. Handa is one of the few places on the Torridonian sandstone which provide true sea-bird cliffs. No other place on the formation can compare with it for numbers of auks, except perhaps Clo Mor, about four miles east of Cape Wrath, where there is a cliff of over 800 feet.

      The splendour of the Torridonian is in the peaks it makes inland. Some are fantastic and others superb. There is only one Suilven and it is undoubtedly the most fantastic hill in Scotland (Plate 3b). It rises to 2,309 feet out of a rough sea of low gneiss. Seen from north and south it has a distinctive shape of a very steep frontal cliff and rounded top called Casteal Liath (the grey castle), then a dip and a lesser knob before a more gentle slope down to the east. But when seen from west or east the extreme thinness of the hill is apparent. Probably the Dolomites would be the nearest place where such an extraordinary shape of a hill could be seen. Suilven means the pillar which is a good name for the hill seen from the west. It is often likened to a sugar loaf, also. There are greyish-white quartzite boulders sprinkled on the top, yet there is a little alp of grass up there and an occasional bed of Rhacomitrium moss. The great terraces of Caisteal Liath itself are but thinly marked by such grasses and sedges

Скачать книгу