It was followed by the Berkefield filter, constructed of baked infusorial earth.
There is some roofing slate along the Rogue river, natural cement, nickel ore, bismuth and wolframite in Douglas county, gypsum in Baker county, fire-clay in Clatsop county, borate of soda on the marsh lands of Harney county, infusorial earth and tripoli in the valley of the Deschutes river, chromate of iron in Curry and Douglas counties, molybdenite in Union county, bauxite in Clackamas county, borate of lime in Curry county, manganese ore in Columbia county, and asbestos in several of the southern and eastern counties.
The organic world (like the world as a whole) arises out of a primitive chaos, namely, the infusorial slime.
Other mineral substances obtained in small quantities are: pyrite, in St Lawrence county; arsenical ore, in Putnam county; red, green and purple slate, in Washington county; garnet in Warren, Essex and St Lawrence counties; emery and felspar, in Westchester county; and infusorial earth in Herkimer county.
The most important export is fish, other items being seaweed, marble, preserved foods, butter and margarine and infusorial earth.