The bed of crystalline salts known as Searles Lake, in southeastern California, contains the most valuable potash-bearing brine known in the United States. This salt body has an exposed surface area estimated at 11 or 12 square miles and an average depth of about 70 feet. For the most part it is firm and compact enough to support a wagon and team even during wet seasons, when it is' sometimes flooded with a thin sheet of water that dissolves the surface salts to a slight extent. The deposit contains in the interstices between the salt crystals a saturated brine the volume of which is estimated to be more than 25 per cent of that of the entire saline mass.