Travels in the Tibet (English Edition)

The route of the caravan is marked by an endless succession of small
deep ditches filled with water, and meandering in dark lines through the
white surface. Numerous trickles of water collect into a rivulet, which
rushes down among the stones. Where the ground is level a swamp is
formed, dome-shaped clumps of moss render it uneven, and between these
stand pools, often of deceptive depth.