A LARGE FOSSIL SEA-SHELL FROM WESTERN QUEENSLAND (Inoceramus maximus)
(length 12¾ inches, breadth 7¼ inches).

The remains of animal and vegetable life found in the older strata agree, as a whole, with those found in other parts of the globe of the same periods. At some time in the mesozoic age the Australian continent must have been separated and have become a continent by itself. This plainly appears in the tertiary period, during which the greater part of Australia seems to have remained an independent dry country. This was also the case during the quaternary period.

Australia has had no ice period. At least but uncertain traces of glacial actions are to be found.

In the tertiary period we must look for the oldest ancestors of the present fauna, in the quaternary for the immediate progenitors, which resemble the present animals, and many of them are remarkable for their size. There has been a kangaroo one-third larger than the present species, there has also been a gigantic animal related to the kangaroo and living on vegetables, the Diprotodon, which was about as large as an elephant. The remains of this animal are so widespread and so numerous as to make it evident that it must have existed wellnigh throughout Australia.

At the time when the country became inhabited by man there still lived one of the great animals of the palæozoic times, namely a bird resembling the ostrich and much larger than the emu. Its bones have been found in the middens of the savages, and the joints show marks of their flint knives.

Among the more recent geological formations is the so-called “desert sandstone,” which is found scattered through a great part of the interior. It contains no sea-shells, and but few remains of plants and of fresh-water shells. There are various opinions in regard to its origin. Some think it was deposited in large lakes, which are supposed to have been very numerous in a remote age. A more probable theory is, however, that the substratum has been disintegrated into sand and stone dust and blown about by the wind.

Australia has no active volcanoes, but extinct ones are numerous. Some of those found in Victoria are believed to have been active in a late prehistoric age.

Among the mineral products of Australia gold is the most important. It had its seat originally in veins of quartz in the oldest rocks. By the disintegration of the rocks during the long geological ages much alluvial gold has been deposited among the sand and the gravel. The running water carries stony substances with it more rapidly than gold, which lags behind on account of its weight. The result is that the deposits increase in quantity as we approach the original seat of the gold, and when circumstances are favourable the gold digger may be handsomely rewarded for his labours.

III
FLORA

Scarcely a flora is to be found with so many peculiarities as the Australian. Still this does not imply that the things which appear so remarkable to the traveller are of equal interest to the botanist, though often they are more so. It is often stated as a curiosity that the Australian “cherry-trees” have the stone outside of the berry, and not inside, as with us in Europe. As a matter of fact this is nothing remarkable, the explanation being simply that what we call the fruit is merely an enlarged berry-like stalk, while the fruit proper is an unsavoury nut, hard as stone, growing at the extreme end of this stalk. Hence the tree is called Exocarpus (“outside fruit”). Similar phenomena are found in other parts of the world.[[23]] The Australian “pear” grows with the large end nearest the stalk; but it is not a pear, just an inedible fruit, hard as wood, of a Proteacea called Xylomelum pyriforme.