Types of Igneous Rocks. An igneous rock is formed by the cooling and crystallization of molten rock. The term igneous is derived from ignius, the Latin word for fire.Scientists have divided igneous rocks into two broad categories based on where the molten rock solidified.ypes of Igneous Rocks. An igneous rock is formed by the cooling and crystallization of molten rock. The term igneous is derived from ignius, the Latin word for fire.
Monongalia County, known locally as Mon County, is a county located in the U.S. state of West Virginia. As of the 2010 census, the population was 96,189, making it the fourth-most populous county in West Virginia. Its county seat is at Morgantown. The county was founded in 1776.
Washington County is a county located in the western part of the U.S. state of Maryland. As of the 2010 census, the population was 147,430. Its county seat is Hagerstown. Washington County was the first county in the United States to be named for the Revolutionary War general (and later President) George Washington. Washington County is one of three Maryland counties recognized by the Appalachian Regional Commission as being part of Appalachia.