There is another line of reasoning, debated by Mr. Wallace, based on the formation of the Palæozoic and Secondary strata from the waste of broken continents and islands occupying generally the site of the existing continents, and separated by insignificant distances of inland sea or extensions from the adjacent oceans. It is soundly based on their lithological structure, as generally indicative of a littoral and shallow water origin, but it seems to me to be only positive so far as it shows that, throughout geological time, some land has existed somewhere within the limits of the present upheaval, and simply negative as to what may or may not have been the condition of what are now the great ocean spaces of the world. Indeed, it would at first sight seem only reasonable to infer, that the very depressions which caused the inundations of Europe and Asia, during the deposition of any important formation, would imply a corresponding elevation elsewhere, in order that the same relative areas of land and water might be maintained. This view has, however, been reduced in its proportions by Dr. Carpenter, who has levelled the results of the recent researches by the _Challenger_ expedition against the advocates of the intermutations of land and ocean, and, in pursuing another line of reasoning from Mr. Wallace, has estimated the solid contents of ocean and land above the sea-level respectively, as bearing the proportion of thirty-six to one. So that, supposing all the existing land of the globe to sink down to the sea-level, this subsidence would be balanced by the elevation of only one thirty-sixth part of the existing ocean floor from its present depth to the same level. It must be admitted that the balance of argument was until lately considerably against the former existence of the country of Atlantis, whose ghostly outlines, however, we could almost imagine to be sketched out by faint contours in the chart illustrative of the North Atlantic portion of the _Challenger_ investigations. But it was not so overwhelming as to entitle us to ignore the story entirely as a fable. I do not conceive it impossible that some centrally situated and perhaps volcanic island may once have existed, sufficiently important to have served as the basis of simple legends, which, under the enchantment of distance and time became metamorphosed and enriched. Mr. A. R. Grote suggests that it is simply a myth founded on the observation of low-lying clouds in a sun-flushed sky, which gave the appearance like islands on a golden sea. Mr. Donelly, on the other hand, in a very exhaustive and able volume, contends first, that Atlantis actually existed, and secondly, that it was the origin of our present civilization, that its kings are represented by the gods of Greek mythology, and that its destruction originated our Deluge story.