“It could eat all the streams we know and still be thirsty. Its name is Ou-dis-sun, the Sacred, the Long.”
“No man of my tribe had seen it, not even my father, the priest. It was magic and I prayed.”
Thse two details show that the narrator is cautious in this new setting. The first sentence states that the river was extremely long, and that it could eat all the streams and still be thirsty. This shows that the narrator believes the river to be very powerful, and he is amazed at its magnitude. The second sentence states that he believes the river to be magical, and that this encouraged him to pray. This shows the reverence he has for the river, and how impacted he is by being in this new setting.