 Complete the following phrase:  Pressing his advantage, the marquis began organizing an assault on the new Paraguayan defenses which López had thrown up along the Pikysyry, south of Asunción Paraguays capital. This stream afforded a strong defensive position which was anchored by the Paraguay River and by the swampy jungle of the Chaco region, both considered to be nearly impassable by a large force. Rather than making a frontal attack on Lópezs line, Caxias had a road cut through the Chaco. The road was finished by early December, allowing the allied forces to outflank the Paraguayan lines and attack from the rear. In three successive battles Ytororó, 