History of the Peloponnesian War

The next day some of the Athenians were building the wall to the north of the central point, while others were collecting stones and timber, and laying them along the line, to the point called Trogilus; keeping in the direction in which their wall of circumvallation would be completed in the shortest distance from the great harbour to the sea.

The Syracusans meanwhile, at the suggestion of Hermocrates, more than of their other generals, were no longer disposed to run the risk of general actions with the Athenians, but thought it better to build a counterwall in the direction in which they intended to carry their works; thinking that if they anticipated them with this, there would be an interruption to their lines; and that, if at that time they should come to oppose them, they themselves would send a part of their forces against them, and have time to occupy the approaches beforehand with their palisade, while the Athenians would cease from their work, and all turn their attention to them.

They went out, therefore, and proceeded to build, beginning from their city, and carrying a cross wall below the Athenian lines, cutting down the olives of the sacred ground, and erecting wooden towers.

The ships of the Athenians had not yet sailed round from Thapsus into the great harbour, but the Syracusans still commanded the sea-shore, and the Athenians conveyed their provisions from Thapsus by land.