The Story of the Hills: A Book About Mountains for General Readers.

by H. N. Hutchinson

The pine woods too, which clothe the hills, are continually being upheaved towards the lower limit of snow, and are gradually withering away in the cooler atmosphere; and wide belts of forest are composed of nothing but dead trees, although some of them have stood for centuries.

Geologists have proved that the Baltic Sea formerly communicated by a wide channel with the North Sea, the deepest depressions of which are now occupied by lakes in the southern part of Sweden; for considerable heaps of oyster-shells are now found in several places on the heights commanding these great lakes. Then we have in Denmark the celebrated "kitchen-middens," heaps of rubbish also largely composed of oyster-shells which the inhabitants, in the "Stone Age," collected from the bottoms of the neighbouring bays. At the present day the waters of the Baltic, into which rivers bring large quantities of fresh water, do not contain enough salt for oysters to grow there; but the oyster-shells prove that the Baltic Sea and these inland lakes were once as salt as the North Sea is now. This can only be explained by supposing that the Baltic was not so shut in then as it is in these days. The bed of the old wide channel has risen, and what once was sea is now land.

Again, it is very probable that the great lakes and innumerable sheets of water which fill all the granite basins of Finland have taken the place of an arm of the sea which once united the waters of the Baltic to those of the great Polar Ocean. And so there must have been upheaval here as well.

The old sea-beaches, now above the level of the highest tides, that are found in many parts of the Scandinavian, Scottish, and other coasts, furnish plain evidence of upheaval.

At the present day, between the lines of high tide and low tide, the sea is constantly engaged in producing sand and shingle, spreading them out upon the beach, mingling them with the remains of shells and other marine animals, and sometimes piling them up, sometimes sweeping them away. In this way a beach often resembles a terrace. When the land is upheaved rapidly enough to carry up this line of beach-deposits before they are washed away by the waves, they form a flat terrace, or what is known as a "raised beach." The old high-water mark is then inland; its sea-worn caves become in time coated with ferns and mosses; the old beach forms an admirable platform on which meadows, fields, villages, and towns spring up; and the sea goes on forming a new beach below and beyond the margin of the old one.

The Scottish coast-line, on both sides, is fringed with raised beaches, sometimes four or five occurring above each other, at heights of from twenty-five to seventy-five feet above the present high-water mark. Each of these lines of terrace marks a former lower level at which the land stood with regard to the sea; and the spaces between them represent the amount of each successive rise of the land. Each terrace was formed during a pause, or interval, in the upward movement, during which the waves had time to make a terrace, whereas, while the land kept on rising, they had no time to do so. Thus we learn that the upheaval of the country was interrupted by considerable pauses.

Sometimes old ports and harbours furnish evidence of upheaval. Thus, the former Roman port of Alaterva (Cramond) in Scotland, the quays of which are still visible, is now situated at some distance from the sea, and the ground on which it stands has risen at least twenty-four feet. In other places the scattered débris shows that the coast has risen twenty-six feet. And by a remarkable coincidence, the ancient wall of Antoninus, which in the time of the Romans stretched from sea to sea, and served as a barrier against the Picts, comes to an end at a point twenty-six feet above the level of high tides. In the estuary of the Clyde there are deposits of mud, containing rude canoes and other relics of human workmanship, several feet above the present high-water mark.

Raised beaches are found on many parts of the coast of Great Britain. Excellent examples occur on the coasts of Devon and Cornwall. On the sides of the mountainous fiords of Norway similar terraces are found up to more than six hundred feet above the sea; and as some of these rise to a greater height at a distance of fifty miles inland, it seems that there was a greater upward movement towards the interior of Norway than on the coasts.

There is a celebrated raised beach on the side of a mountain in North Wales, known as Moel Tryfaen, where the writer gathered a number of marine shells at a height of 1,357 feet.

But Scandinavia and Great Britain are not the only parts of Europe where an upward movement has taken place, for the islands of Nova Zembla and Spitzbergen show evidence of the same kind; and the coast of Siberia, for six hundred miles to the east of the river Lena, has also been upraised. On the banks of the Dwina and the Vega, 250 miles to the south of the White Sea, Murchison found beds of sand and mud with shells similar to those which inhabit the neighbouring seas, so well preserved that they had not lost their colours.