Edgar Wallace,
Terror Keep — Chapter 18
(1927)
“ Reeder was too dazed even to realise that he was lying half buried in a heap of debris, until Gray pulled him back to the passage."They're using a gun, a quick-firer!" he gasped.Mr. Reeder did not reply. He was gazing fascinated, at something that was happening in the middle of the cave, where the water was leaping at irregular intervals from some mysterious cause. Then he realised what was taking place. Great rocks, disturbed by the concussion, were falling from the roof. He saw the motor boat heel over to the right, swing round again, and head for the open. ”
