The shore between Santarem and Obydos, where we shall arrive this evening, seems more populous than the regions we have been passing through. As we coast along, keeping close to the land, the scenes revive all our early visions of an ancient pastoral life. Groups of Indians—men, women, and children—greet us from the shore, standing under the overarching trees, usually trained or purposely chosen to form a kind of arbor over the landing-place,—the invariable foreground of the picture, with the “montaria” moored in front. One or two hammocks are often slung in the trees, and between the branches one gets a glimpse of the thatched roof and walls of the little straw cottage behind. Perhaps if we were to look a little closer at these pictures of pastoral life, we should find they have a coarse and prosaic side. But let them stand. Arcadia itself would not bear a too minute scrutiny, nor could it present a fairer aspect than do these Indian homes on the banks of the Amazons. The primitive forest about the houses is usually cleared, and they stand in the midst of little plantations of the cacáo-tree, mingled with the mandioca shrub, from the roots of which the Indians make their flour, and occasionally also with the India-rubber-tree, though, as the latter grows plentifully in the forest, it is not often cultivated. The cacáo and the India-rubber they send to Pará, in exchange for such domestic goods as they require. We have passed so close to the shore to-day that it has been easy to make geological observations from the deck. For a considerable distance above Santarem we have followed drift cliffs, resting upon sandstone; the drift of the same reddish color, and pasty, clayey consistence, and the sandstone seemingly the same in character, as that of Monte Alégre. _August 27th._—Villa Bella. Last evening we stopped to wood at the town of Obydos, but without landing; keeping straight on to this port, on the southern side of the river, at the mouth of the river Tupinambaranas. Here we were very cordially received by Dr. Marcus, an old correspondent of Mr. Agassiz, who has several times sent specimens from the Amazons to the Cambridge Museum. To-night we are to start in canoes on an excursion to some of the lakes in the neighborhood of this port.