“Stretch?” said the woman who’d smiled at him. “You make it sound like a sentence in the mines.”

“I don’t mean it like that-quite.” He grinned his most disarming grin. Most of the tourists grinned back. A few stayed sober-faced, likely the ones who suspected the gibe was real and the grin put on. There was some truth in that. He knew it, but the tourists weren’t supposed to.

He went on, “In a bit, I’ll take you over to the donkeys for the trip down into the Trench itself. As you know, we try to keep our mechanical civilization out of the park so we can show you what all the Bottomlands were like not so long ago. You needn’t worry. The donkeys are very sure-footed. We haven’t lost one — or even a tourist — in years.” This time, some of the chuckles that came back were nervous. Probably only a couple of this lot had ever done anything so archaic as getting on the back of an animal. Too bad for the ones just thinking about that now. The rules were clearly stated. The pretty Highhead girls looked particularly upset. The placid donkeys worried them more than the wild beasts of the Trench.

“Let’s put off the evil moment as long as we can,” Radnal said. “Come under the colonnade for half a daytenth or so and we’ll talk about what makes Trench Park unique.”

The tour group followed him into the shade. Several people sighed in relief. Radnal had to work to keep his face straight. The Tarteshan sun was warm, but if they had trouble here, they’d cook down in the Trench. That was their lookout. If they got heatstroke, he’d set them right again. He’d done it before.

He pointed to the first illuminated map. “Twenty million years ago, as you’ll see, the Bottomlands didn’t exist. A long stretch of sea separated what’s now the southwest section of the Great Continent from the rest. Notice that what were then two lands’ masses first joined in the east, and a land bridge rose here.” He pointed again, this time more precisely. “This sea, now a long arm of the Western Ocean, remained.”