sulphate

The ground at the place where we stopped for the night, was incrusted with a layer of sulphate of soda, and hence, of course, was without water.

The salt here, and in other parts of Patagonia, consists chiefly of sulphate of soda with some common salt.

In both countries the salt-lakes occupy shallow depressions in the plains; in both the mud on the borders is black and fetid; beneath the crust of common salt, sulphate of soda or of magnesium occurs, imperfectly crystallized; and in both, the muddy sand is mixed with lentils of gypsum.