And, as I have shown, the same great law which gradually depressed the Atlantic continent, and raised the lands east and west of it, is still at work: the coast of Greenland, which may be regarded as the northern extremity of the Atlantic continent, is still sinking "so rapidly that ancient buildings on low rock-islands are now submerged, and the Greenlander has learned by experience never to build near the water's edge," ("North Amer. of Antiq.," p. 504.) The same subsidence is going on along the shore of South Carolina and Georgia, while the north of Europe and the Atlantic coast of South America are rising rapidly. Along the latter raised beaches, 1180 miles long and from 100 to 1300 feet high, have been traced.
When these connecting ridges extended from America to Europe and Africa, they shut off the flow of the tropical waters of the ocean to the north: there was then no "Gulf Stream;" the land-locked ocean that laved the shores of Northern Europe was then intensely cold; and the result was the Glacial Period. When the barriers of Atlantis sunk sufficiently to permit the natural expansion of the heated water of the tropics to the north, the ice and snow which covered Europe gradually disappeared; the Gulf Stream flowed around Atlantis, and it still retains the circular motion first imparted to it by the presence of that island.
The officers of the Challenger found the entire ridge of Atlantis covered with volcanic deposits; these are the subsided mud which, as Plato tells us, rendered the sea impassable after the destruction of the island.
It does not follow that, at the time Atlantis was finally ingulfed, the ridges connecting it with America and Africa rose above the water-level; these may have gradually subsided into the sea, or have gone down in cataclysms such as are described in the Central American books. The Atlantis of Plato may have been confined to the "Dolphin Ridge" of our map.
ANCIENT ISLANDS BETWEEN ATLANTIS AND THE MEDITERRANEAN, FROM DEEP-SEA SOUNDINGS
The United States sloop Gettysburg has also made some remarkable discoveries in a neighboring field. I quote from John James Wild (in Nature, March 1st, 1877, p. 377):
"The recently announced discovery by Commander Gorringe, of the United States sloop Gettysburg, of a bank of soundings bearing N. 85° W., and distant 130 miles from Cape St. Vincent, during the last voyage of the vessel across the Atlantic, taken in connection with previous soundings obtained in the same region of the North Atlantic, suggests the probable existence of a submarine ridge or plateau connecting the island of Madeira with the coast of Portugal, and the probable subaerial connection in prehistoric times of that island with the south-western extremity of Europe."… "These soundings reveal the existence of a channel of an average depth of from 2000 to 3000 fathoms, extending in a northeasterly direction from its entrance between Madeira and the Canary Islands toward Cape St. Vincent…. Commander Gorringe, when about 150 miles from the Strait of Gibraltar, found that the soundings decreased from 2700 fathoms to 1600 fathoms in the distance of a few miles. The subsequent soundings (five miles apart) gave 900, 500, 400, and 100 fathoms; and eventually a depth of 32 fathoms was obtained, in which the vessel anchored. The bottom was found to consist of live pink coral, and the position of the bank in lat. 36° 29' N., long. 11° 33' W."
The map on page 51 shows the position of these elevations. They must have been originally islands;—stepping-stones, as it were, between Atlantis and the coast of Europe.
Sir C. Wyville Thomson found that the specimens of the fauna of the coast of Brazil, brought up in his dredging-machine, are similar to those of the western coast of Southern Europe. This is accounted for by the connecting ridges reaching from Europe to South America.
A member of the Challenger staff, in a lecture delivered in London, soon after the termination of the expedition, gave it as his opinion that the great submarine plateau is the remains of "the lost Atlantis."