Sinclair, W. J., cited, [152].
Sink lakes, [421].
Sinks, in limestone, [182].
Sinter, calcareous, [184];
siliceous, [194].
Sinter columns, formation of, [185].
Sinter deposits, [184].
Sjögren, Otto, cited, [225].
Skaptár fissure in Iceland, [99].
Skyline, straight, of mature upland, [170].