Springs, fissure, [190], [195];

surface, [181];

thermal, [190].

Stability, not the order of nature, [4].

Stacks, [233];

elevated, [249], [343].

Stage of adolescence, [169], [170].

Stairway, cascade, [376].

Stalactites, growth of, [184].

Stalagmites, formation of, [185].