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slate

(Encyclopedia)slate, fine-grained rock formed when sedimentary rocks such as shale are metamorphosed by great pressure. Slate splits into perfectly cleaved, broad thin layers; this characteristically regular and pl...

Polaris

(Encyclopedia)Polaris pōlârˈĭs [key] or North Star, star nearest the north celestial pole (see equatorial coordinate system). It is in the constellation Ursa Minor (see Ursa Major and Ursa Minor; Bayer designat...

Jim Crow laws

(Encyclopedia)Jim Crow laws, in U.S. history, statutes enacted by Southern states and municipalities, beginning in the 1880s, that legalized segregation between blacks and whites. The name is believed to be derived...

Theodore Roosevelt National Park

(Encyclopedia)Theodore Roosevelt National Park, 70,447 acres (28,531 hectares), W N.Dak., in the Badlands and on the Little Missouri River; est. 1947. There are three units—the North Unit, the Elkhorn Ranch Unit,...

Wuxi

(Encyclopedia)Wuxi or Wusih both: wo͞o-shē [key], city (1994 est. pop. 863,100), S Jiangsu prov., China, on the Grand Canal and the north bank of Tai lake. It is a silk-producing center. Foods (especially grains)...

cockle

(Encyclopedia)cockle, common name applied to the heart-shaped, jumping or leaping marine bivalve mollusks, belonging to the order Eulamellibranchia. The brittle shells are of uniform size, are obliquely spherical, ...

conglomerate, in geology

(Encyclopedia)conglomerate, in geology, sedimentary rock composed largely of pebbles or other rounded particles whose diameter is larger than 2 mm (.08 in.). Essentially a cemented gravel, conglomerates are formed ...

boulder, in geology

(Encyclopedia)boulder, large rock fragment formed by detachment from its parent consolidated rock by weathering and erosion. In engineering and geology, especially in the United States, the term is applied to loose...

mesa, in geology

(Encyclopedia)mesa māˈsə [key] [Span.,=table], name given in the SW United States to a small, isolated tableland or a flat-topped hill. Two or more of the sides are steep and usually perpendicular and some have ...

Tompkins, Douglas Rainsford

(Encyclopedia)Tompkins, Douglas Rainsford, 1943–2015, American business executive, conservationist, and philanthropist, b. Conneaut, Ohio. In 1964, he and his first wife, Susie Tompkins Buell, founded The North F...