For six nonstop hours, the four of them crossed the four cardinal check drifts streaming from the central chamber at five hundred and twelve paces beneath Windpit.
After completing the survey of the western dense green rock doorstep, they returned to the central hub, their boots clicking on the bronze drainage grate that covered the deep sump. The air remained clean and steady, whistling softly down the spiral stairwell they had cleared and drawing upward through the main upright shaft in a nonstop, gentle drain tube.
Kezra turned her compass to true north, sighting down the dark mouth of the northern gallery.
“Northern drift,” Kezra announced, adjusting the strap of her sounding rod. “Two hundred and fifty-six paces to the outer edge boundary.”
In the northern drift, the tunnel cut through massive, flawless hard speckled rock, fully free of open fractures, water seeps, or backup stone veins. The rock here was a dark, uniform pluton, composed of linked crystals of hard black rock and plagioclase that had cooled slowly miles beneath the ancient surface. Above their heads, old zinc-coated air-flow pipes hung from iron brackets leaded into the ceiling arch, silent and rusted, leftovers of the air-flow systems installed during the great digging decades before.
