range of hills, north-central Uruguay. With the Grande Range (Cuchilla Grande) to the east, it defines the basin of the Negro River, Uruguay's major river. The range extends southward from a rugged highland area near the Brazilian border for approximately 125 miles (200 km) and terminates at the confluence of the Negro and Uruguay rivers, the Rincón de las Gallinas. It separates a basalt upland to its west from the Negro River basin, frequently as an escarpment exhibiting interbedded basalts and red sandstones. Its geologic structure is different from that of the Grande Range. Maximum elevations, which are nowhere very great, approach 1,300 feet (400 m) at the hills of Lunarejo and Virgen.