Agora Image: 2012.41.0807 (Section ΟΟ 491): Drain area, north, looking west. Indicated with H is the Heavy Wall parallel to Great Drain, C is the cutting in bedrock scarp for continuation of Heavy Wall. D is the Great Drain wall, x is the poros block, P is the packing stones in the back of the drain wall, I is the higher road strosis and II is the lower road strosis,