Viedma describes it as of great extent, situated in a sort of bay, or vast amphitheatre of the mountains, from the steep ravines of which ran down the many streams which filled it, chiefly derived from the melting of the snows in the north-west: he skirted it for twelve leagues to its extremity in that direction, and estimated its extreme length at about fourteen; its width, he says, might be from four to five leagues. Some dark patches amongst the snow on the distant heights indicated the clumps of trees of which the Indians had spoken; but the few which Viedma was able to examine were not what he had been led to expect; he speaks of them as resembling a wild cherry, with a fruit in appearance not unlike it, though of a more orange colour, and without a stone and very tasteless; the wood stunted, and so crooked as to be entirely unfit for anything but burning. May it not have been the crab-apple? We know there are plenty of apples further north in the same range. Describing the appearance of the Cordillera from the head of the lake, he says, towards the north it looked like a vast table-land stretching from east to west; but it had a different appearance in the south, breaking into steep and broken peaks, for the most part covered with snow. The Indians said that neither to the north nor south was the main chain passable by man or beast for a very long distance. They all concurred in stating that a large river issued from the south-east angle of the lake, which they believed to be the great river of Santa Cruz[21]; Viedma, unfortunately, was not able to examine it, as he wished, in consequence of the apparent swelling of the mountain-torrents, which alarmed the Indians lest they should so increase the rivers as to prevent their recrossing them on their return; nor were they very wrong, for, by the time they got back to the Chico, they found it a wide and rapid stream no longer fordable. It was proposed that some of the Indians who could swim should tow Viedma across on a balsa, which they set to work to construct of hides and sticks, but when completed, it looked so frail and dangerous a ferry, that the Spaniards preferred running the risk of swimming their horses over. This they accomplished without accident, and reached San Julian's in safety again on the 3rd of December, after nearly a month's absence, during which they were much indebted to the Indians for their friendly aid, and knowledge of the country through which they passed.