In accordance with this view, we can, perhaps, understand some facts which will be again alluded to in our chapter on Geographical Distribution; for instance, the fact of the productions of the smaller continent of Australia now yielding before those of the larger Europaeo-Asiatic area.

Thus, also, it is that continental productions have everywhere become so largely naturalised on islands.

On a small island, the race for life will have been less severe, and there will have been less modification and less extermination.

Hence, we can understand how it is that the flora of Madeira, according to Oswald Heer, resembles to a certain extent the extinct tertiary flora of Europe.