A military earthwork above Goodwood. The area is about two furlongs. It has a double vallum. The situations of the portæ are still to be traced in the east, west, and north. The fortifications of the ancient Britons being circular, it is probable that the Trundle is British. The fortified encampments of the Romans were square; examples may be seen at the Broyle, near Chichester, and on Ditching Hill.