It is generally recognised by science that what is now dry land, on the surface of our globe, was once the ocean floor, and that what is now the ocean floor was once dry land. Geologists have in some cases been able to specify the exact portions of the earth's surface where these subsidences and upheavals have taken place, and although the lost continent of Atlantis has so far received scant recognition from the world of science, the general consensus of opinion has for long pointed to the existence, at some prehistoric time, of a vast southern continent to which the name of Lemuria has been assigned.