This Earth was once the home of a sapient dinosaur-like civilization. Unfortunately, this civilization is now extinct and what only remains of their time is rectangles of brick and stones and a big black temple-like building.
Upon exploring the place, Lobsang discovered that the area around temple is radioactive. Getting away from the temple, the Mark Twain crew explored the nearby caves to find only corpses. On one of the corpses, Joshua found a golden ring adorned with sapphires and took it with him to serve as a trophy.
After the discovery of the Rectangles in 2030, parties of researchers were sent here by universities in order to know more. They discovered that buried under the dust were traces of cities, roads and canals.
After a few years, the funding money ran out and the archeologists packed their stuff and left.
In another Earth, Joshua, travelling with Bill Chambers aboard the Shillelagh in search of Sally and the trolls, noticed that the ring he found in the Rectangles ten years ago disappeared from where it was hanging on one of the wall of the twain. It made him realized that he had to go to the Rectangles to find Sally.
Three days later, Joshua and Bill finally arrived at the Rectangles and were welcomed by Monica who had been waiting for them for several days and brought them to Earth West 1,617,524.
Sally had promised the beagles to bring them more ray guns from the Rectangles with the help of Monica and Finn in exchange of a chance to talk to the trolls. The beagles stapled Joshua to make sure the humans wouldn't step away and fulfill their end of the bargain.
Sally, Monica and Finn went to the Rectangles with the ring and opened the radioactive temple, but for only eight minutes according to Finn. Monica, already sick with leukemia, volunteered to go fetch the weapons.
Inside the temple, after walking around in low corridors, she found rack upon rack of ray guns.
With the ray guns fetched, they rushed back to Earth West 1,617,524 to save Joshua, who were promised a honourable death by Petra, following the beagles' traditions.