Significados de continental extensions en inglés

Those who believe in vast continental extensions will never investigate means of distribution.

I was not able to get a definite answer from Lyell (On the continental extensions of Forbes and others.

If they would not work then "every one who believes in single centres will have to admit continental extensions" (Ibid.

We both give up creation, and therefore have to account for the inhabitants of islands either by continental extensions or by occasional transport.