The Blessing Papers
"As the huge door settled to the ground, there was a sigh like the sound of a thousand mourners. It startled Corvine, and he looked high up to see the overhead lights going out one by one. Soon he was cast into an almost absolute darkness. Only the thin yellow strips on the nearby panel remained, like the phantom lights seen behind eyes tightly squeezed. Since he knew the cave had been sealed with no exit, the old man backed to the wall, slid to the floor and waited with his slack arms crossed over his raised knees. He did not fear death; he knew now he had been prepared for that possibility. Instead, he was thankful that no one could ever find the cave or what lay buried within it.
The darkness was heavy and thick like ice. The only thing that moved was the light dust that fell gently to the vast, unseen solidity of the floor. The bodies of the two men were like shadows on shadow."
From the Prologue, page 7
When The Blessing Papers first appeared, a screenplay was proposed and written, with input from the author. But as happens in the movies, time lapsed without the film being made.