3 adjectives to describe fosse

In this manner the camp was protected not only by a double fosse, but also by a double row of defenders, some of whom, placed on the bridges, could from this elevated and sheltered position throw their missiles farther and with a better aim; while the others, placed on the vallum, nearer to the enemy, were protected by the bridges from the missiles which showered down upon them.

At present the most interesting part of the great mound is the actual fosse and vallum.

On the south side of this tumulus, and not far from it, was a semicircular fosse, which, when I first saw it, was 6 feet deep.

3 adjectives to describe  fosse