Igneous rocks are formed from the solidification of molten rock material. There are two basic types. Intrusive igneous rocks crystallize below Earth's surface and the slow cooling that occurs there allows large crystals to form.Examples of intrusive igneous rocks are diorite, gabbro, granite, pegmatite, and peridotite.abbro is a coarse-grained, dark colored, intrusive igneous rock that contains feldspar, pyroxene and sometimes olivine. The specimen shown above is about two inches (five centimeters) across. Obsidian is a dark-colored volcanic glass that forms from the very rapid cooling of molten rock material.
McLennan County, Texas. McLennan County is a county located on the Edwards Plateau in Central Texas. As of the 2010 census, its population was 234,906. Its county seat is Waco. The U.S. census 2016 county population estimate is 247,934. The county is named for Neil McLennan, an early settler.
Location of Waco on a map. Waco is a city found in Texas, The United States Of America. It is located 31.55 latitude and -97.15 longitude and it is situated at elevation 147 meters above sea level. Waco has a population of 124,805 making it the 21st biggest city in Texas. It operates on the CDT time zone, which means that it follows the same time zone as Houston.