Hole in bedrock; dumped filling used in leveling.
Probably a natural water line, tending to wash out, has been cut back for various purposes, and finally all filled in to make level bedding for 4th c., ... Ca. 350-270 B.C ... Hesperia Suppl. 23 (1989), p. 70 ... Agora XII, p. 394 ... Agora XXIII, p. 333.