evidence: Río Pascua, the 50-km-long outlet of Lago San Martín/O'Higgins (see northeast corner of fig. 29), has no name on ONC T-18, in spite of its important discharge (510 m3 s-1). South of Lago San Martín/O'Higgins and Fiordo Calén (top center of fig. 29), the Southern Patagonian Ice Field (SPIF or, in Spanish, Hielo Patagónico Sur) extends more than 330 km between the watersheds of Lagos San Martín/O'Higgins, Viedma, and Argentino (fig. 30) on the east and the fjords of the Pacific Ocean on the west. Its total area (including 1,500 km2 of contiguous glaciers) was 13,500 km2 in 1945, reduced to about 13,000 km2 in 1986. The ice divides between its outlet glaciers, and the equilibrium lines in 1986 have been determined from Landsat TM images by Aniya and others (1996). The number of outlet glaciers in successive ranges of areas is given below. A description of the Southern Patagonian Ice Field and its outlet glaciers from north to south is as follows (see figs. 29-39).