We report here, for the first time, the finding of a 24 to 31 m deep, 10,000 y old, water-saturated and highly hydraulically conductive salt layer composed of idiomorphic halite crystals in the coastal area of the Dead Sea. The high hydraulic conductivity of the layer was evidenced by laboratory and field tests and by the rapid fluctuations of the water table, in a well penetrating the layer, following variations in the water level of the Dead Sea. Such layers may lead to intensive and rapid flow of water and non-polar liquids. ¿ American Geophysical Union 1995