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Before the formation of the coal forests volcanoes have been active - Arthur's Seat in Edinburgh's Hollyrood Park is what remains of a volcanic cone - but it was around the Clyde Basin
(Gargunnoch, the Fintry, Campsie Hills and Renfrewshire uplands) and in the south (the Birrenswark Hills) that the major thickness of lava erupted. Still the continents drifted northwards, and between 280 and 195
million years ago Scotland passed through the latitudes now occupied by North Africa and Arabia. The climate became hot and dry and deserts developed, resulting in such windblown dunes as the red sandstone's that are
extensively quarried in Dumfriesshire. Upto 65 million years ago the climate remained warm, but not so intensely hot and arid as before, and the deserts gave way to pleasant landscape clothed with ferns and cycads and
inhabited by reptiles. During this time Scotland was surrounded by warm shallow seas of ever changing shape. Sand and mud derived from the land were deposited in these seas and consolidated to form the sandstone's and
shales that appear fairly extensively in the Hebrides (in Raasay, Skye, and Eigg) and fringe the mainland of East Sutherland. Their importance, however, is that they floor the North and Hebridean Seas and form, or have
potential as, oil reserves. Since the closing of the ancient ocean 400 million years ago, the Euro American continent had been joined by other continents from the south, and by 250 million years ago Scotland was in the
middle of a supercontinent. This vast supercontinent moved northwards, carrying Scotland into the northern hemisphere. Before Scotland reached its present latitude, the supercontinent started to break up and between 165
and 65 million years ago the South Atlantic ocean opened, with a gradual separation between South Africa and South America. Between 61 and 55 million years ago volcanoes poured out hundreds of metres of lava
along the west coast of Scotland. As the molten lava cooled, it sometimes left extraordinary shapes like the hexagonal columns at Fingal's Cave on Staffa or the towers and spires of the Quirang in Skye. These volcanoes
spread along a line approximately north and south and might eventually have opened a rift. However, the rift that did eventually open the North Atlantic ocean was situated west of the British Isles. Volcanic activity
associated with the continuing separation of North America and Europe is still active in Iceland today. In the last 2 million years ice sheets must have been present in Scotland on at least 17 occasions. At its most
extensive the ice would have reached a thickness of over 3000 feet and formed a continuous ice cap with the sheets over all Scandinavia. Between these glacial events, warmer periods intervened. Erosion caused by frost
and ice movement was enormous - glens were hollowed out, rocks worn down and smoothed, valleys and lochs deepened and fjords formed in the west of Scotland. The end of the last Ice Age, which came around 10,000 years
ago, left a desolate landscape. Freed of the enormous burden of ice the land rose again, while the melting glaciers raised sea levels. The relative rate of this rising varied, leading sometimes to the submergence of
coastal features and sometimes to the production of raised beaches, of which the Old Course of St. Andrews is a famous example.As the climate improved, Scotland was covered first by tundra and then rapidly by
forests, except in Caithness and the Northern Isles. Birches grew almost everywhere while pines became established as did oak. Animals, including elk, ox, beaver, boar, wolf, bear and lynx lived in these forests, as
well as those species that still survive in Scotland. About 6000 years ago the tree line reached its highest since the last glaciation. At the same time also a blanket of bogs became established and have progressively
increased at the expense of the forests, although woodland clearance by man has had the greatest impact in this. In colonising Scotland man inherited the outcome of at least 3000 million years of natural development of
the land and 400 million years of the natural development of living things upon it. Here the history of Scotland begins. |
