Note 15 — Chapter I

Narrative of the U. S. Exploring Expedition during the Years 1838–42. Phila., 1844. Tom. IV, p. 334. “We soon reached the Butte prairies (on Columbia River) which were extensive, and covered with tumuli or small mounds, at regular distances asunder. As far as I could learn there is no tradition among the natives relative to them. They are conical mounds thirty feet in diameter, about six to seven feet high above the level, and many thousands in number. Being anxious to ascertain if they contained any relics, I subsequently visited these prairies, and opened three of the mounds, but found nothing in them but a pavement of round stones.”