saltpits

Therefore as I live, saith the LORD of hosts, the God of Israel, Surely Moab shall be as Sodom, and the children of Ammon as Gomorrah, even the breeding of nettles, and saltpits, and a perpetual desolation: the residue of my people shall spoil them, and the remnant of my people shall possess them.

And as for other things that belong unto us, of the tithes and customs pertaining unto us, as also the saltpits, and the crown taxes, which are due unto us, we discharge them of them all for their relief.