Here the ridge of low mountains running north-west and south-east crosses the river, and forms the western boundary of the plain through which we have just passed.[3] This great plain, or valley, is about sixty miles wide in a straight line; while on the right and left it extends to a great distance. It is a fertile and delightful country, shaded by thick groves of tall timber, watered by small ponds, and lying on both sides of the river. The soil is rich, and capable of any species of culture; but, in the present condition of the Indians, its chief production is the wappatoo-root, which grows spontaneously and exclusively in this region. Sheltered as it is on both sides, the temperature is much milder than that of the surrounding country. Through its whole extent, it is inhabited by numerous tribes of Indians, who either reside in it permanently, or visit its waters in quest of fish and wappatoo-roots. We gave it the name of the Columbia Valley. COFFIN ROCK. Among some interesting islands of basalt, there is one called Coffin Rock, situated in the middle of the river, rising ten or fifteen feet above high-freshet water. It is almost entirely covered with canoes, in which the dead are deposited, which gives it its name. In the section of country from Wappatoo Island to the Pacific Ocean, the Indians, instead of committing their dead to the earth, deposit them in canoes; and these are placed in such situations as are most secure from beasts of prey, upon such precipices as this island, upon branches of trees, or upon scaffolds made for the purpose. The bodies of the dead are covered with mats, and split planks are placed over them. The head of the canoe is a little raised, and at the foot there is a hole made for water to escape. THEY REACH THE OCEAN. Next day we passed the mouth of a large river, a hundred and fifty yards wide, called by the Indians Cowalitz. A beautiful, extensive plain now presented itself; but, at the distance of a few miles, the hills again closed in upon the river, so that we could not for several miles find a place sufficiently level to fix our camp upon for the night. Thursday, Nov. 7.--The morning was rainy, and the fog so thick, that we could not see across the river. We proceeded down the river, with an Indian for our pilot, till, after making about twenty miles, the fog cleared off, and we enjoyed the delightful prospect of the OCEAN, the object of all our labors, the reward of all our endurance. This cheering view exhilarated the spirits of all the party, who listened with delight to the distant roar of the breakers.