Half a mile from the point of his first descent, the sergeant found a shoal. It was a flat space of shallow water—discoverable by the color of the bottom. The water was not over four feet deep. It was a remarkably level shoal place.
He whistled on his fingers. When Patrolman Willis reached him, he pointed to the cliffs directly across the beach from the shallow water. Lurid yellow tints stained the cliff walls. Odd masses of fallen stone dotted the cliff foot. At one place they were piled high. That pile looked quite natural—except that it was at the very center of the shore line next the shoal.
"This rock's yellow," said Sergeant Madden, rumbling a little. "It's mineral. If we had a Geiger, it'd be raising hell, here. There's a mine in there. Uranium. If a ship came down on rockets, an' landed in that shoal place yonder ... why ... it wouldn't leave a burned spot comin' down or takin' off, either. Y'see?"
Patrolman Willis said: "Look here, sergeant—"
"I'm in command here," growled Sergeant Madden. "Huks didn't booby trap. Proud as hell, and touchy as all get-out, but not killers. Not crazy killers, anyhow. You go get up yonder. Up where we started down. Then go on away. Back to the squad ship. If I don't come along, anyhow you'll know what's what when the Aldeb comes."
Patrolman Willis expostulated. Sergeant Madden was firm. In the end, Patrolman Willis went away. And Sergeant Madden sat at ease and rested until he had time enough to get back to the squad ship. It was true that the Huks didn't booby trap. They hadn't had the practice, anyhow, eighty years ago. But this was a very important matter. Maybe they considered it so important that they'd changed their policy concerning this.
Wheezing a little, Sergeant Madden pulled away large stones and small ones. An opening appeared behind them. He grunted and continued his labor. Nothing happened. The mouth of a mine shaft appeared, going horizontally into the cliff.