* 
122 LOWER AMAZONS—PARA TO OBYDOS. ° Cuap. VI. 
occurs so frequently throughout the Amazons region ; the strong current 
of the river sets full against them in the season of high water, and 
annually carries away large portions. The clay in places is stratified 
alternately pink and yellow, the pink beds being the thickest, and of 
much harder texture than the others. When I descended the river in 
1859, a German Major of Engineers, in the employ of the Government, 
told me that he had found calcareous layers, thickly studded with 
marine shells interstratified with the clay. On the top of the Tabatinga 
lies a bed of sand, in some places several feet thick, and the whole 
formation rests on strata of sandstone, which are exposed only when the 
river reaches its lowest level. Behind the town rises a fine rounded 
hill, and a range of similar elevations extends six miles westward, 
terminating at the mouth of the Trombetas, a large river flowing through 
the interior of Guiana. Hills and lowlands alike are covered with a 
sombre rolling forest. The river here is contracted to a breadth of 
rather less than a mile (1738 yards), and the entire volume of its waters, 
the collective product of a score of mighty streams, is poured through 
the strait with tremendous velocity.* It must be remarked, however, 
that the river valley itself is not contracted to this breadth, the opposite 
shore not being continental land, but a low alluvial tract, subject to 
inundation more or less in the rainy season. Behind it lies an extensive 
lake, called the Lago Grande da Ville Franca, which communicates with 
the Amazons, both above and below Obydos, and has therefore the 
appearance of a by-water or an old channel of the river. This lake is 
about thirty-five miles in length, and from four to ten in width ; but its 
waters are of little depth, and in the dry season its dimensions are much 
lessened. It has no perceptible current, and does not therefore now 
divert any portion of the waters of the Amazons from their main course 
past Obydos. 
I remained at Obydos from the 11th of October to the 19th of 
November. I spent three weeks here, also, in 1859, when the place 
was much changed through the influx of Portuguese immigrants and 
the building of a fortress on the top of the bluff. Itis one of the 
pleasantest towns on the river. The houses are all roofed with tiles, 
and are mostly of substantial architecture. ‘The inhabitants, at least at 
the time of my first visit, were naive in their ways, kind and sociable. 
Scarcely any palm-thatched huts are to be seen, for very few Indians 
now reside here. It was one of the early settlements of the Portuguese, 
and the better class of the population consists of old-established white 
families, who exhibit, however, in some cases, traces of cross with the 
Indian and negro. Obydos and Santarem have received, during the 
last eighty years, considerable importations of negro slaves ; before that 
* It was formerly believed that the river at the strait of Obydos could not be 
sounded on account of its great depth and the velocity of the current. Lieut. Herndon, 
of the United States navy, succeeded in doing so, however, in 1852. He found a 
depth of 30 to 35 fathoms, but in one place he thought he had not touched the 
bottom at 40 fathoms. Von Martius, estimating the depth in the middle at 60 
fathoms, and on the side at 20, and the velocity of the current at 2°4 feet per second, 
estimated that 499,584 cubic feet of water passed through the strait in each second of 
time. The tides are felt here in the dry season, but the flood does not press back the 
current of the Amazons. 
