Most likely this was an earthen wall, with wooden gates.

I saw a city made of earth, with earthen walls.

Around the capital was a tall earthen wall for defense with 17 gates.

In the center of the new commercial street, I found the public cemetery, enclosed by an earthen wall.

The large earthen walls of the fort are still visible today.

The powder line led across the floor to a tiny opening in the earthen wall.

It is a natural or artificial wall, usually earthen and often parallels the course of a river.

No remains of the earthen walls have been found, however.

The castrum can only be made out by an earthen wall.

This morning, there were three small leaks in the earthen wall at the lake.