The air was noticeably thinner there and their burdens heavier. A short distance beyond they came to a small rock monument; Craig’s turn-back point.

The next day they found the quartz crystals in place. A mile farther was the vein the mica had come from. Of the other minerals Craig had hoped to find, however, there were only traces.

The fourth day was an eternity of struggling up the now-steeper canyon under loads that seemed to weigh hundreds of pounds; forcing their protesting legs to carry them fifty steps at a time, at the end of which they would stop to rest while their lungs labored to suck in the thin air in quick, panting breaths.

It would have been much easier to have gone around the mountain. But the Chasm was supposed to be like a huge cavity scooped out of the plateau beyond the mountain, rimmed with sheer cliffs a mile high. Only on the side next to the mountain was there a slope leading down into it.