Grell reveals some of the secrets of Skartaris in Warlord 5 (Feb/March 1977).
At the top of the story Machiste leaves Travis Morgan and Tara. He is going back to his own city, Kiro, but we will see him again in a few months.
Morgan and Tara wind up encountering another dinosaur, and while fleeing from it come across a doorway into a cave.
There, they wind up in another high tech chamber. Morgan activates a machine which shows them the history of Skartaris. The city was founded by Atlanteans, fleeing their home after it sunk beneath the waves. The eternal sunlight of Skartaris boosted their natural advantages, and they became far more advanced than their ancestors had been. Unfortunately, the city states scattered across Skartaris went to war with each other, in what looks like a nuclear conflict. The radiation from this had the effect of transforming those closest to the blast. Those nearest are now the lizard men, cave people further out, and the furthest away resemble humans and Atlanteans. Travis also learns that Deimos had found this chamber, and activated the history machine himself, which explains where he got his "book of blood."
Having left the door to the cave open, Travis and Tara have to fight off some prowling wolves, which sends them further into the cave.
Travis finds a subway of sorts, and wonders if they can use it to travel back to Shamballah. Tara is pretty freaked out by all the high tech, and refuses to enter the car. Smart move. Once Travis enters the door slams shut and the car takes off, with such force that it throws Morgan across the car, knocking him out.
When he wakes he finds the subway car has stopped. Leaving it, Morgan finds himself back on the surface world, the last place he now wants to be.