Now the F-2 had roped out and Jane and Jerry were in the canyonlands west of Amarillo, the part of the Texas Panhandle people called the Breaks. They’d been running cross-country in a flat plain, and then the earth opened up in front of them. The Canadian River of the Panhandle was not a major river now, but it had been a very major river during the last ice age, and it had done some dreadful things to the landscape here. Real mesas, not the slumped hills of the south High Plains. Mesas weren’t mountains. They were not vigorous upthrustings in the landscape. Mesas were remnants, mesas were all that was left, after ages of stubborn resistance to rainsplash and sheetwash and channel cutting. The mesas had a layer of hard sandstone, a caprock, up on top, but below that caprock layer was a soft, reddish, weak, and treacherous rock that was scarcely petrified mud. That rock was so weak you could tear off clods of it and crumble it to dust with your fingers. The mesas were toothless and terribly patient and all wrinkled down the sides, eaten away with vertical gullies, their slopes scattered with the cracked remains of undereaten sandstone slabs.