Just above Fray Bentos the islands dot the river more plentifully than in almost any other part of the great stream. As is the case on the Paraná, it is difficult enough at times to distinguish between these and the true bank on the Argentine shore; both are equally lowly and each covered with the same density of willows and native scrub. Amongst these larger islands, however, whose surface may comprise several square miles, are numerous smaller pieces of land, and some quite diminutive specimens that can lay claim to no more than a few yards of area. These are baby islands--young territories that have only just succeeded in raising their heads above water. For an island here is conceived, grows, and dies in a fashion that is vegetable rather than purely earthy. The fact is not really curious, seeing that vegetation is directly concerned in their birth. The conception of one of these is evident even now. A tangle of the thick leaves of the camelota--the water plant with its mauve hyacinth-like flower--has in its downward floating course fouled the earth of a shallow in mid-stream. The arrested clump of green has already inveigled other objects to keep it company in its trap. A few sticks and branches and tufts of grass are already fast in the embrace of the powerful stems and green leaves, while at the end that faces the stream the water-driven sand has risen at the obstacle, and has shyly protruded a small round hump or two above the ripples. The life of the thing is as uncertain as that of a seedling or of a human child. Under favourable conditions it will grow and solidify year by year until from the few leaves and sticks will have extended some square miles of tree-covered soil. On the other hand, it may be swept remorselessly away in its earliest days ere the tentative formation has had time to secure sufficiently firm hold of the earth. [Illustration: ON THE URUGUAY RIVER.] [Illustration: A URUGUAYAN STREAM. To face p. 230.] In any case the life of these islands is comparatively short, and fresh floods and currents are forming some and destroying others all the while. During these periods of flood many of them would seem possessed of the characteristics of icebergs. Detached by the irresistible force of the currents, great fragments of the vegetation and camelota plant that cling to their sides go swirling down the stream. Though they can boast no polar bears, they are occasionally freighted with other beasts whose neighbourhood is equally undesirable. On such occasions snakes and many four-footed specimens of northern creatures form the unwilling tenants of these frail rafts of vegetation. It is said that many years ago one of unusually large size struck the shore of Montevideo itself, disgorging four jaguars, who entered the town as much to their own terror as to that of the inhabitants.