The People of the River by Edgar Wallace

NORTH of the Akasava country and on the left bank of the Isisi is a veritable forest of elephant grass. Here in the cool of the evening, and later, the hippo come to wallow and for social intercourse. Here, too, buck and the small but terrible buffalo come to bathe and drink.

For ten miles without a break the jungle runs and there is no tree or hill behind the green curtain to reveal what manner of country lies beyond.