Here, earlier in the year, eleven bridges had been constructed, each a labor of accuracy; and perhaps as many swampy places had been "corduroyed" by carpeting them with long parallel poles.

Now the first difficulty began.
Some of the bridges had sunk below the level, and the approaches had to be corduroyed to a practicable grade.

Others again were humped up like tom-cats, and had to be pulled apart entirely.

In spots the "corduroy" had spread, so that the horses thrust their hoofs far down into leg-breaking holes.

The experienced animals were never caught, however.
As soon as they felt the ground giving way beneath one foot, they threw their weight on the other.
Still, that sort of thing was to be expected.