Some iron ore, gypsum, salt and limestone are also produced.
The occurrence of red deposits in western Australia, Scotland, the Ural mountains, in Michigan, Montana and Nova Scotia, &c., associated in some instances with the formation of gypsum and salt, clearly points to the existence of areas of excessive evaporation, such as are found in land-locked waters in regions where something like desert conditions prevail.
In the neighbourhood are deposits of gypsum and salt.
The state contains deposits of iron, gypsum, marl, phosphate, lignite, ochre, glass-sand, tripoli, fuller's earth, limestones and sandstones; and there are small gas flows in the Yazoo Delta.
Other minerals that have been discovered but have not been industrially developed are gypsum, lignite and cement rock.