Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.1): between the years 1826 and 1836 : describing their examination of the southern shores of South America, and the Beagles's circumnavigation of the globe

328 SAN TADEO BLACK RIVEK. DeC. 1829. no deep channel ; and, except in very fine weather, an attempt to cross is hazardous. At its mouth, the breadth is about a quarter of a mile, but "within the entrance it increases for a short distance: at three miles up, it is three hundred yards, and thence gra- dually diminishes. The shores are a mixture of clay and sand; and the country, on both sides, is low and marshy, abound- ing with brant-geese, ducks, teal, and snipe. The land, near the mouth of the river, is studded with dead trees (a species of pine, about twenty feet high), which appear to have been killed by the sea overflowing the banks; (6) as it does at high-water for several miles. Three miles from the entrance this river divides into two branches, one leading N.W., and the other eastward. Con- sidering the latter, from Byron's description, to be the proper course, Lieutenant Skyring followed it. At nine miles from the mouth, a stream was found falling into the river from the north, in every respect differing from the principal stream ; the water being fresh, dark, and clear, and the current constantly running down, uninfluenced by the tide ; while the water of the river was brackish and turbid, and affected by the ebbing and flowing of the tide, although, at that distance, its effect was much diminished. The shores of the Black River, as this new stream was called, are thickly wooded, which is not the case with the principal stream. They had entered it about a hundred yards before they discovered that they had left the main river ; but being desirous of proceeding, they followed its windings, the next day, for three leagues ; during the greater part of which distance, they found a strong current against them, and were also much im- peded by fallen trees lying in the bed of the river. In many parts they dragged their boat along by the help of overhanging branches, or projecting roots ; and the width, generally, was not more than fifty yards. As no piragua could pass there. Lieutenant Skyring felt assured that he was not in the right stream ; therefore, returning to the main river, he proceeded (bj Or by an earthquake wave. — R. F