From One River, by Wade Davis:
“They believe,” Tim explained, “that as you move from one valley to the next, you must thank the mountain guardians for their protection. Every time they cross over a divide, they place a quid of coca on the rock cairns that mark the high passes and blow prayers into the wind.”
“For everything there must be a payment,” Adalberto said, his thoughts and Tim’s finally achieving a certain symmetry. He lifted the chukuna stick from his gourd, placed it into his mouth, and bit down on the lime-coated end. A small trickle of green saliva ran out the corner of his lip.
“You are not Christians,” he said.
“No,” Tim agreed.