The roads have now become so impassable that ambulances with wounded men can no longer run between here and Fredericksburg.

This valley opened into the Dana gorge, which is here neither so narrow nor so impassable as at its opening into the plateau.

Yet that short distance was so impassable that, save for the more deadly fire, a quarter of a mile might have divided us.

So impassable did it then become that even men were compelled to engage the services of a cargador to carry them across "pickaback."