Distribution of Fauna and Flora

The proved existence on continents separated by great oceans of similar or identical species of fauna and flora is the standing puzzle to biologists and botanists alike. But if a link between these continents once existed allowing for the natural migration of such animals and plants, the puzzle is solved. Now the fossil remains of the camel are found in India, Africa, South America and Kansas: but it is one of the generally accepted hypotheses of naturalists that every species of animal and plant originated in but one part of the globe, from which centre it gradually overran the other portions. How then can the facts of such fossil remains be accounted for without the existence of land communication in some remote age? Recent discoveries in the fossil beds of Nebraska seem also to prove that the horse

[1. Pop. Sc. Review, July, 1878.]

originated in the Western Hemisphere, for that is the only part of the world where fossil remains have been discovered, showing the various intermediate forms which have been identified as the precursors of the true horse. It would therefore be difficult to account for the presence of the horse in Europe except on the hypothesis of continuous land communication between the two continents, seeing that it is certain that the horse existed in a wild state in Europe and Asia before his domestication by man, which may be traced back almost to the stone age. Cattle and sheep as we now know them have an equally remote ancestry. Darwin finds domesticated cattle in Europe in the earliest part of the stone age, having long before developed out of wild forms akin to the buffalo of America. Remains of the cave-lion of Europe are also found in North America.

Turning now from the animal to the vegetable kingdom it appears that the greater part of the flora of the Miocene age in Europe--found chiefly in the fossil beds of Switzerland--exist at the present day in America, some of them in Africa. But the noteworthy fact about America is that while the greater proportion are to be found in the Eastern States, very many are wanting on the Pacific coast. This seems to show that it was from the Atlantic side that they entered the continent. Professor Asa Gray says that out of 66 genera and 155 species found in the forest east of the Rocky Mountains, only 31 genera and 78 species are found west of these heights.

But the greatest problem of all is the plantain or banana. Professor Kuntze, an eminent German botanist, asks, "In what way was this plant" (a native of tropical Asia and Africa) "which cannot stand a voyage through the temperate zone, carried to America?" As he points out, the plant is seedless, it cannot be propagated by cuttings, neither has it a tuber which could be easily transported. Its root is treelike. To transport it special care would be required, nor could it stand a long transit. The only way in which he can account for its appearance in America is to suppose that it must have been transported by civilized man at a time when the polar regions had a tropical climate! He adds, "a cultivated plant which does not possess seeds must have been under culture for a very long period ... it is perhaps fair to infer that these plants were cultivated as early as the beginning of the Diluvial period." Why, it may be asked, should not this inference take us back to still earlier times, and where did the civilization necessary for the plant's cultivation exist, or the climate and circumstances requisite for its transportation, unless there were at some time a link between the old world and the new?

Professor Wallace in his delightful Island Life, as well as other writers in many important works, has put forward ingenious hypotheses to account for the identity of flora and fauna on widely separated lands, and for their transit across the ocean, but all are unconvincing, and all break down at different points.

It is well known that wheat as we know it has never existed in a truly wild state, nor is there any evidence tracing its descent from fossil species. Five varieties of wheat were already cultivated in Europe in the stone age--one variety found in the "Lake Dwellings" being known as Egyptian wheat, from which Darwin argues that the Lake dwellers "either still kept up commercial intercourse with some southern people, or had originally proceeded as colonists from the South." He concludes that wheat, barley, oats, etc., are descended from various species now extinct, or so widely different as to escape identification, in which case he says: "Man must have cultivated cereals from an enormously remote period." The regions where these extinct species flourished, and the civilization under which they were cultivated by intelligent selection, are both supplied by the lost continent whose colonists carried them east and west.

From the fauna and flora we now turn to man.