Assertion: archipelago's base | /r/HasProperty | southern
Facets:
Source sentences:
text: The islands spread out in the shape of a triangle, with those south of Palawan, the Sulu Archipelago, and the island of Mindanao outlining (from west to east, respectively) its southern base and the Batan Islands to the north of Luzon forming its apex.
text: The archipelago stretches about 1,150 miles (1,850 km) from north to south, and its widest east-west extent, at its southern base, is some 700 miles (1,130 km).