The Wonder Book of Volcanoes and Earthquakes

by Edwin J. Houston

But these charming, though fallacious, ideas were rudely overthrown by the sounding line and the drag-net. It had long been known that pieces of coral rock were brought up by dredging apparatus from the bottom of the ocean at all depths, but it was eventually shown that such pieces of coral rock never contained living animalculæ, when brought from water at greater depths than from 100 to 120 feet.

It puzzled scientific men no little at first to explain this apparent inconsistency. If the coral polyp could not live in water at greater depths than from 100 to 120 feet, how could the presence of coral rock at a depth of thousands of feet be explained? Happily, however, this problem was solved by the great naturalist, Charles Darwin, who showed that coral islands can only be formed in parts of the ocean whose beds are sinking at the same gradual rate at which the coral rock is being deposited. The presence, therefore, of coral islands on the bed of the Pacific, as well as along parts of its coasts, are, to scientific men, as good indications of its gradual sinking as if such facts had been written in the clearest language.

But there are other instances of gradual changes of level besides the bed of the Pacific. About 600 miles along the coast of Greenland, from Disco Bay, near lat. 69° N., south to the Firth of Igaliko, lat. 60° 43' N., the bed of the ocean has been slowly sinking through 400 years. Old buildings and islands have been covered by the waters, so that fishermen have been compelled to provide new poles for their boats. As Sir Charles Lyell remarks:

"In one place the Moravian settlers have been obliged more than once to move inland the poles upon which their large boats are set, and the old poles still remain beneath the water as silent witnesses of the change."

Besides these gradual changes of level there are many others, but only one more need be cited: the gradual movements of the coasts of North America between Labrador and New Jersey that are rising in some places, and sinking in other places.

The evidences of these gradual changes of level are sometimes of such a character that he who runs may read them. One of the most interesting is, perhaps, that of the old Roman temple of Jupiter Serapis, at Pozzuli, on the borders of the Mediterranean. This temple, when completed, was 124 feet in length and 115 feet in width. Its roof was supported by forty-six columns, each forty-two feet in height, and five feet in diameter. Only three of these columns are now standing. They give, however, unquestionable evidence of having been submerged for about half their height. Nor, indeed, is the evidence wanting that this submergence continued a considerable time; for, while the lower twelve feet of the columns remain smooth and unaffected, yet, for a distance of nine feet above this portion, they have been perforated by various stone-boring mollusks of a species still living in the Mediterranean. This witnesses that the columns, when submerged, were buried in mud for twelve feet, and surrounded by water nine feet deep. According to Dana, the pavement of the temple is still under water. The fact that another pavement exists below it shows that these changes of level had occurred before the temple was deserted by the Romans. It appears, that, prior to 1845, a gradual sinking of this part of the coast had been going on, but that since then there has ensued a gradual rising.

The evidences of these gradual changes of level in the land and water surfaces of the earth cannot be doubted by even the most skeptical. Again and again has the dry land disappeared below the surface of the waters of the ocean. Again and again, the ocean's bed has been raised to the surface and been converted into dry land. Suppose we attempt to follow one of the latter movements.

We will imagine an extensive area to have slowly appeared above the ocean. In due process of time this land surface, which we will assume to have continental dimensions, gradually becomes covered with plant and animal life. If it remains above the water for a sufficient length of time, its simple plants and animals acquire more and more complex forms, so as to make it difficult to detect any traces of the original species from which they have descended, or, more correctly, ascended. Moreover, where favorable conditions exist, the continent becomes peopled with men, who gradually advance from barbarism to semi-barbarism and eventually become a most highly civilized nation, sending to different parts of the world colonies, who carry with them the language and religious customs of the land of their birth.

But, a sudden or paroxysmal change of level occurs. The highly developed and densely populated region is suddenly swept out of existence and completely covered by the waters of the ocean until, in a few thousand years, all traces of its existence have so completely disappeared that but few, if any, can be found willing to acknowledge it ever had an existence.

Such, it is claimed, was the fate of the fabled Continent of Atlantis. It will, therefore, be interesting to endeavor briefly to review its past history and to read some of the things that have been written about this part of the world, which appears in the opinion of some of the ancients to have actually existed.