“Probably seepage from underground springs, like those that feed the canals,” he thought. “But it wasn’t there before.”
His glance fell on the floor of the corridor. The drifted dust lay over it thickly as when they had entered. But there were no footprints in it now. No prints at all except those he was now making.
A horrible doubt, a feeling of unreality, clawed at Carse. The un-Martian dampness, the vanishing of their footprints—what had happened to everything in the moment he’d been inside the dark bubble?
He came to the end of the square stone corridor. And it was closed. It was closed by a massive slab of monolithic stone.
Carse stopped, staring at the slab. He fought down his increasing sense of weird unreality and made explanation for himself.
“There must have been a stone door I didn’t see—and Penkawr has closed it to lock me in.”
He tried to move the slab. It would not budge nor was there any sign of key, knob or hinge.
Finally Carse stepped back and leveled his proton-pistol. Its hissing streak of atomic flame crackled in the rock slab, searing and splitting it.
The slab was thick. He kept the trigger of his gun depressed for minutes. Then, with a hollowly reverberating crash the fragments of the split slab fell back in toward him.
But beyond, instead of the open air, there lay a solid mass of dark red soil.