HOW AUSTRALIA. BECAME AS ISLAND.

Otago Witness, Issue 1875, 28 October 1887, Page 32

HOW AUSTRALIA. BECAME AS ISLAND.

About the beginning of the tertiary period, howevor, jiift after the chalk was all deposited, and just before the comparatively modern clays jind sandstones of the London b,ipii\ began tobelaiddown, anarmof the sea binko up the connection winch once subsisted bpiwopu Australia and the rest of the world. ],!\>bably by a land bridge, via Java, Sumatra, the Malitypeninsula,andA&iagenerally. "But how do you know,"' asks the candid inquirer, " ihat such a connection ever existed at. all ?" Simply this, most laudable investigator — because there are large land mammals in

Australia. Now, large land mammals do not swim across a broad ocean. There are none in New Zealand, none in the Azores, none in Fiji, none in Tahiti, none in Madeira, none in Teneriffe — none, in short, in any oceanic island which never at any time formed part of a great continent. How could there be, indeed? The mammals must necessarily have got there from somewhere ; and whenever we find islands like Britain, or Japan, or Newfoundland, or Sicily, possessing large and abundant indigenous quadrupeds of the same general type as adjacent continents, we see at once that the island must formerly have been a mere peninsula, like Italy or Nova Scotia at the present day. The very fact that Australia encloses a large group of biggish quadrupeds, whose congeners once inhabited Europe and America, suffices in itself to prove beyond question that uninterrupted land communication must once have existed between Australia .and those distant continents. In fact, to this day a belt of very deep sea, known as Wallace's Line, from the great naturalist who first pointed out its far-reaching zoological importance, separates what is called by science ; " the Australian province" on the south-west from "the Indo-Malayan province" to the north and east of it. This belt of deep sea divides off sharply the plants and animals of the Australian type from those of the common Indian and Burmese pattern. South of Wallace's Line we now find several islands, big and small, including New Guinea, Australia, Tasmania, the Moluccas, Celebes, Timor, Amboyna, and Banda. All these lands, whose precise geographical position on the map must of course be readily remembered in this age of school boards and universal examination, by every pupilteacher and every Girton girl, are now divided by minor straits of much shallower water, but they all stand on a great submarine bank, and obviously formed at one time parts of the same wide Australian continent, because the animals of Australian type are still found in every one of them. No Indian or Malayan animal, of the larger sort (other than birds) is to be discovered anywhere south of Wallace's Line. That narrow belt of deep sea, in short, forms an ocean barrier which has subsisted there without alteration ever since the end of the secondary period. From that time to this, as the evidence shows us, there has never been any direct land communication between Australia and any part of the outer world beyond that narrow line of division. — From "A Fossil Continent," in the""Cornhill Magazine."