If Atlantis were lowlands connecting the West Indian Islands with America, the other islands mentioned by Plato may have been the Azores, also greatly increased in extent by the lowering of the ocean; and the overwhelming of this lowland, on the melting of the ice at the close of the glacial period, may be that great catastrophe that is recorded on both sides of the Atlantic, but is more clearly remembered in the traditions of America, because all the highlands there had been covered with ice, and the inhabitants were restricted to those that were overwhelmed by the deluge. I approached this subject from the side of Natural History. I was driven to look for a refuge for the animals and plants of tropical America during the glacial period, when I found proofs that the land they now occupy was at that time either covered with ice or too cold for genera that can now only live where frost is unknown. I had arrived at the conclusion that they must have inhabited lowlands now submerged, and following up the question, I soon saw that the very accumulation of ice that made their abode impossible provided another for them by the lowering of the sea. Then pursuing the subject still further, I saw that all over the world curious questions concerning the distribution of races of mankind, of animals, and of plants, were rendered more easy of solution on the theory that land was more continuous once than now; that islands now separated were then joined together, and to adjacent continents; and that what are now banks and shoals beneath the sea were then peopled lowlands. I have said that during the glacial period, if, as I believe, it was contemporaneous in the two hemispheres, the sea must have stood at least 1000 feet lower than it now does. It may have been much lower than this, but I prefer to err on the safe side. When geologists have mapped out the limits of ancient glacier and continental ice all over the world, it will be possible to calculate the minimum amount of water that was abstracted from the sea; and if by that time hydrographers have shown on their charts the shoals and submerged banks that would be laid dry, fabled Atlantis will rise before our eyes between Europe and America, and in the Pacific the Malay Archipelago will give place to the Malay Continent. Here is a noble inquiry, an unexplored region of research, at the entrance of which I can only stand and point the way for abler and stronger minds; an inquiry that will lead to the knowledge of the lands where dwelt the peoples of the glacial period who lived before the flood.