The country had become more and more difficult as we advanced, and frequently we had to wind our way in single file round the mountains by a narrow path scarcely affording foothold to our horses.  Sometimes on one side, sometimes on the other were steep precipices, over which, by a false step, either we or our animals might be whirled into the roaring torrent below.  Now we had to force a road through the tangled forest to cut off an angle of the stream, and then to pass along narrow gorges, beetling cliffs frowning above our heads, and almost shutting out the light of day.