b'are limestone and sandstone. Sand and Coal is an important source ofgravel are plentiful in our state, and energy. It is a black rocklike materialthese are used in making highways and that crumbles easily when hit. Much ofconcrete. eastern Ohio has coal, found in layersSalt is necessary for humans and beneath the grounds surface. Coal isanimals to live. Early explorers looked burned, which creates energy. At onefor salt as they traveled into new time people heated their homes withareas. In the Ohio Country, they found coal and cooked on coal-burning stoves. a good supply. In fact, Licking County Petroleum (oil) and natural gas arewas named for the salt licks found also sources of energy. Today the U.S.there. A salt lick is a place where salt imports most of its oil from foreignis deposited (usually by a spring) and countries. In the late 1800s, about halfanimals come to lick it. Salt was used of all the oil used in the U.S. came fromfor preserving meat before refrigera- Ohio. Oil fields were established intion was invented. Today salt is still Perry, Fairfield, Licking, Allen, Hancock,mined in Ohio, mostly in the north- and other counties. Today oil productioneastern part of the state. continues here in Ohio. Natural gas isOhio is a top producer of clay in also still produced, especially in south-the United States. It is plentiful in the eastern Ohio.eastern Allegheny region of the state.Pottery, tiles, pipes, bricks, and otherhousehold objects are made of thisclay. Some of the largest potteries inthe world can be found in Ohio.Minerals used to be plentiful here,too. Iron ore, coal, petroleum, andnatural gas have been important prod-ucts to our state. In the 1800s, Ohiowas one of the most important sourcesof iron in the world, but after mining itfor decades, the iron ore is almostgone. Southern Ohio became developedprimarily because of the iron industry. Petroleum oil originates in marine waters. Itforms as the tiny remains of plants settleOne town in Lawrence County is even in sand and mud. Over a very long period ofnamed Ironton. time the oil accumulates in sand and shale,from which it can be extracted.Graphic (O)page 7'