Thus begins a streak of bad luck for the Nautilus.
While passing through a series of "new islands"—that is, islands that are a million years old instead of ten million years old—Aronnax talks to Nemo. He tells him that one day, these islands will become a new continent.
Nemo tells him, "It is not new continents that the earth needs, but new men!" (1.19.4).
While looking at some rock outcroppings underwater, Aronnax gets to talking about the same stuff with Conseil, and we get a little synopsis of how life made it from the oceans onto land.
A couple of days after Christmas, Nemo appears after a long absence and tells Aronnax they're headed for the island of Vanikoro, the site of two famous shipwrecks back at end of the 18th century and early in the 19th century.
When they get to the site, Nemo whips out a little box he has retrieved from one of the wrecks. It contains the original orders for one of the captains, written by Louis XVI. (This would probably be more exciting to you if you were French, so don't worry if you're not exactly pumped.)