Among the larger lakes may be mentioned Toba; Maninyu, west of Fort de Kock; Singkara, south-east of Fort de Kock; Korinchi, inland from Indrapura; and Ranua, in the southwest.
Singkara Lake (44 sq.
Solok lies on the Sumami, which, flowing from the south to the lake of Singkara, prolongs the valley of the Sumpur to the Middengebergte.
Copper has been worked in the Padang highlands (most largely in the district of Lake Singkara) and at Muki in Achin.
There is a railway connecting not only the coalfields of the Ombilin valley with Padang, but also the Ombilin river and the Lake of Singkara with the most productive and densely populated plateaus and valleys, north and south of the line of the volcanoes Singalang, Merapi and Sago.