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After going on in this way for some distance, they came to another crater very similar to the first, only the sides of it, instead of being formed, like the first, of perpendicular cliffs, consisted of steep, sloping banks of volcanic sand and gravel.
Werner affirmed that all rocks, of whatever character, had been formed by precipitation from this sea as the waters cooled; that even veins have originated in this way; and that mountains are gigantic crystals, not upheaved masses. In a word, he practically ignored volcanic action, and denied in toto the theory of metamorphosis of rocks through the agency of heat.
Ages rolled on; vegetation appeared as the volcanic rock disintegrated; crystal lakes were formed and rivers, fed by frequent rains and melting snows, flowed to the sea. This comparatively new island is Iceland. The book of nature here is open; the print is clear; and the language is so plain that he who can read may learn the story.
They come up from the desert about the first of June, and are driven back again to the arid countries as soon as the autumn storms begin. In the very high land they are few, and to be left to their own devices; but now we entered a new sort of country. Below Farewell Gap and the volcanic regions one's surroundings change entirely.
The sun rose out of the water, the mist began to melt, and rolling back, uncovered a line of surf and a belt of rough hillside. Then volcanic cliffs, a sandy isthmus, and a cluster of masts and funnels got distinct, and Lister fixed the glasses on a white stripe across a cinder hill. His hand shook, but he steadied the glasses and saw the stripe was a row of huge letters.
On the leeward side, several black and very fresh-looking streams of lava run into the sea, and the whole coast for some height above the shore shows most vigorous volcanic action. Elsewhere the rock is red and broken, and lateral cones abound near the base.
The almost entire absence of associated grasses, which forms so remarkable a feature in the vegetation of this island, may perhaps be accounted for by the land having been aboriginally covered with forest-trees. The soil is volcanic; in several parts we passed over slaggy lavas, and craters could clearly be distinguished on several of the neighbouring hills.
Pitcairn, the history of which you are now going to read, is also possibly of volcanic origin, and its high crags and sharp peaks seem as if they must have been thrown up by some sudden force; but as it is in the midst of a sea covered with coral islands, and has been supposed by some to be itself partially formed by coral insects, it may be well that you should hear a little of the wonderful growth of coral islands, which, though formed so differently from those of which you have been reading, are yet, when once their tops have risen above the waves, clothed in the same manner with fair growth, to prepare them for the presence of man.
But of violent, or catastrophic, change there is no trace. Even the volcanic outbursts have flowed in even sheets over the old land surface; and the long lines of the horizontal terraces which remain, testify to the geological insignificance of such earthquakes as have taken place.
Since the fossil shells were embedded in sand near the coast, these volcanic islands have undergone considerable alterations in size and shape by the wasting action of the waves of the Atlantic beating incessantly against the cliffs, so that the evidence of a vast lapse of time is derivable from inorganic as well as from organic phenomena.
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