In Stargate SG-1 they are searching for the Lost City in season 8, however in the Stargate Atlantis pilot it is referred to as Atlantis. When is the name found? Or the connection between the Lost City and Atlantis made?
O'NEILL: Terra Atlantis.
JACKSON: Terra's Earth. Atlantis ...
CARTER: The lost city of Atlantis?!
JACKSON: Are you say the lost city of the Ancients is here? (pointing at the image of Earth)
CARTER (also pointing): Antarctica.
O'NEILL: Subo glacios.
JACKSON: Under the ice. The city we've been looking for is under the ice of Antarctica.
CARTER: It's been on Earth the whole time?
However, after arriving at the Antarctic base, it becomes immediately apparent that the base is too small to be a city
JACKSON: The dome's too small. It's like Taonas. It's obviously not a city, it's just an outpost of some kind.
CARTER: This isn't Atlantis?
In the pilot episode of Stargate : Atlantis, we rejoin Daniel Jackson at the Antarctic outpost;
JACKSON: We've gotten closer and closer to finding the location of the Lost City but it turns out we've been looking in the wrong place all along. (He walks over to a whiteboard on which are drawn six Stargate coordinates with the numbers 1-6 above them.) Now, we thought we had a Stargate address -- six symbols representing coordinates in space that determine the location of the planet the Ancients went to after they left Antarctica. Now, recently we determined a seventh symbol. (He picks up a pen and draws the symbol representing Earth on the board to the right of the other symbols.)
WEIR: The point of origin, Earth.
JACKSON: That's not it.
McKAY: Then your address must be incorrect.
JACKSON: Not incorrect… incomplete.
(He draws another symbol in between the sixth symbol and the Earth symbol.)
WEIR: What are you saying, Doctor Jackson?
(Daniel numbers the newest symbol 7 and the Earth symbol 8.)
JACKSON: It's an eight symbol address. What we're looking for may be further away than we ever imagined, but it's not out of reach.
JACKSON: Atlantis. I think we can go there.