...r fortress than a casual railroad embankment often proves, it would be difficult to find; and as for a sunken road, what possibilities of victory or disaster lie in that obstruction, let Waterloo and Fredericksburg bear witness. At Antietam it was a low, rocky ledge, prefaced by a corn-field. There were woods, too, and knolls, and there were other corn-fields; but the student of that battle knows one corn...