Alfred Russel Wallace
"In this archipelago there are two distinct faunas rigidly circumscribed, which differ as much as do those of Africa and South America... yet there is nothing on the map or on the face of the islands to mark their limits. The boundary line passes between islands closer together than others belonging to the same group. I believe the western part to be a separated portion of continental Asia, while the eastern is a fragmentary prolongation of a former west Pacific continent".