_September 13th._—This morning the steamer dropped anchor at the little town of Coari on the Coari River,—one of the rivers of black water. We were detained at this place for some hours, taking in wood; so slow a process here, that an American, accustomed to the rapid methods of work at home, looks on in incredulous astonishment. A crazy old canoe, with its load of wood, creeps out from the shore, the slowness of its advance accounted for by the fact that of its two rowers one has a broken paddle, the other a long stick, to serve as apologies for oars. When the boat reaches the side of the steamer, a line of men is formed some eight or ten in number, and the wood is passed from hand to hand, log by log, each log counted as it arrives. Mr. Agassiz timed them this morning, and found that they averaged about seven logs a minute. Under these circumstances, one can understand that stopping to wood is a long affair. Since we left Coari we have been coasting along close to the land, the continental shore, and not that of an island. The islands are so large and numerous in the Amazons, that often when we believe ourselves between the northern and southern margins of the river, we are in fact between island shores. We have followed the drift almost constantly to-day,—the same red drift with which we have become so familiar in South America. Sometimes it rises in cliffs and banks above the mud deposit, sometimes it crops out through the mud, occasionally mingling with it and partially stratified, and in one locality it overlaid a gray rock in place, the nature of which Mr. Agassiz could not determine, but which was distinctly stratified and slightly tilted. The drift is certainly more conspicuous as we ascend the river; is this because we approach its source, or because the nature of the vegetation allows us to see more of the soil? Since we left Manaos the forest has been less luxuriant; it is lower on the Solimoens than on the Amazons, more ragged and more open. The palms are also less numerous than hitherto, but there is a tree here which rivals them in dignity. Its flat dome, rounded but not conical, towers above the forest, and, when seen from a distance, has an almost architectural character, so regular is its form. This majestic tree, called the Sumaumeira (Eriodendron Sumauma), is one of the few trees in this climate which shed their leaves periodically, and now it lifts its broad rounded summit above the green mass of vegetation around it, quite bare of foliage. Symmetrical as it is, the branches are greatly ramified and very knotty. The bark is white. It would seem that the season approaches when the Sumaumeiras should take on their green garb again, for a few are already beginning to put out young leaves. Beside this giant of the forest, the Imbauba (Cecropia), much lower here, however, than in Southern Brazil, and the Taxi, with its white flowers and brown buds, are very conspicuous along the banks.