"The Lost World" is the name of a 1912 novel by Arthur Conan Doyle about a group of adventurers exploring a plateau in South America populated by dinosaurs.
First series appearance of cave ducks.
Although several episodes in the series prior to this feature time travel, this episode is set in the present and does not feature any time travel (despite featuring dinosaurs and "cave ducks."
The clip in the intro theme song of Webby hiding in a basket comes from this episode.