URUGUAY (officially the Oriental Republic of the Uruguay, and still locally called the Banda Oriental, the "eastern shore" of the Uruguay river), the smallest independent State in South America. It lies between Brazil on the north and the estuary of the Rio de la Plata on the south, extending from the Uruguay river to the Atlantic coast. It has a sea-board of some 120 miles, a shore-line on the Plata of 235 miles and one of 27o miles along the Uruguay. The southern part of the country is mostly un dulating plains, an extension eastward of the Argentine Pampas. The coast-line is fringed with tidal lakes and sand dunes ; the banks of the two bordering rivers are low, unbroken stretches of level land. The northern section of the republic presents greater variety of relief, with occasional ridges and low ranges, alternat ing with broad valleys, a true southward extension of southern Brazil. None of the sierras or mountains of Uruguay exceed 2,000 ft. in elevation.
There are no large rivers within the territory of Uruguay. The Rio Negro, which crosses the country from north-east to south west, is the largest stream. Throughout most of its length it is not navigable, its one river port being the town of Mercedes, 20 m. from its junction with the Uruguay. No other streams are naviga ble except for vessels of light draught. The Santa Lucia, the Queguay and the Cebollati are the principal water courses. These, as well as the Uruguay, are fed by numerous smaller streams (arroyos), affording an intricate network of drainage. The Uruguay river offers navigable waters along the border for steamers of 14 ft. draught from the island of Martin Garcia at its mouth to Paysandu, and above that point for smaller vessels to the falls at Salto, 200 m. in all. Beyond here navigation is interrupted by rapids. (C. L. C. ; G. M. McB.) Geology.—The eastern and southern half of Uruguay is a low, rolling prairie, whose subsoil consists of weathered ancient schist and granite, through which protrude some low ridges composed of less weathered rocks. In central and north-central Uruguay a basement of ancient schist is overlain by nearly horizontal Per mian beds, which form a low plateau. The north-western part of
Uruguay is occupied by a southward extension of the Parana plateau of southern Brazil. This plateau is formed of horizontal beds of Triassic red sandstone of continental origin, which are in places faulted and capped by sheets of Triassic basalt. The plains of Uruguay are covered with Pleistocene deposits of sand and clay like those found on the pampas of Argentina and with alluvial beds. (G. McL. Wo.) Climate.—Uruguay enjoys the reputation of possessing an excellent climate from the viewpoint of human health and com fort. The latitude ensures a fair uniformity of temperature throughout the year, the average for the summer months of January and February being 71° F and that of the coldest month, July, being 5o° ; frost is almost unknown. Moreover, the climate of both summer and winter is marked by great variability from day to day, due to the passing of cyclonic storm centres. Brusque windshifts are common, the hot northerly zonda sometimes being followed immediately by the chill pampero from the south-west and bringing a sudden drop in temperature. These changes, while less extreme than in the pampas of the Argentine, give a middle latitude character to the climate of Uruguay. There are no decided rainy and dry seasons. A rainfall maximum is reached in the autumn (April and May), not in the winter months as is of ten supposed even by the residents of the country. Winter rains are most frequent but autumn rains are heaviest. The mean annual precipitation is about 35 in., decreasing with distance from the sea, but everywhere well distributed throughout the year. Many of the summer-time tormentas are thunderstorms, convectional and purely local in character. These do not always bring rain and are seldom accompanied by hail. Fogs are frequent from May to October, but seldom last all day on land. There are well de veloped land and sea breezes, especially in the summer season, when their influence is welcome.