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Smith, William

(Encyclopedia)Smith, William, 1769–1839, English geologist. Through direct observation as a canal-site surveyor, Smith made a systematic study of the geological strata of England and identified the fossils peculi...

epoch

(Encyclopedia)epoch, unit of geologic time that is a subdivision of a period. The Pleistocene and Holocene epochs, for example, are divisions of the Quaternary period. Epoch is also used to describe a short length ...

era

(Encyclopedia)era, period of historic time. In geology, it is the name applied to large divisions of geological process, e.g., Paleozoic era (see geology). In chronology an era is a period reckoned from a fixed poi...

plate tectonics

(Encyclopedia)CE5 Plate tectonics: Map of the world showing major plates and plate boundaries CE5 Plate tectonics: Schematic model of the oceanic crust, showing the three types of plate boundaries plate tect...

parallax

(Encyclopedia)CE5 The trigonometric parallax of a star, expressed by the angle θ, is a measure of its apparent motion against the background of more distant stars as a result of the earth's motions in its orbit...

Islamic State in Iraq and the Levant

(Encyclopedia)Islamic State in Iraq and the Levant: see Islamic State. ...

Family Compact, in French and Spanish history

(Encyclopedia)Family Compact, several alliances between France and Spain in the form of agreements between the French and Spanish branches of the Bourbon family. The first of the three compacts, the Treaty of the E...

Organization for Security and Cooperation in Europe

(Encyclopedia)Organization for Security and Cooperation in Europe (OSCE), international organization established as the Conference on Security and Cooperation in Europe (CSCE) in 1973, during the cold war, to promo...

William and Mary in Virginia, College of

(Encyclopedia)William and Mary in Virginia, College of, mainly at Williamsburg; state supported; coeducational; chartered 1693, opened 1694 by Episcopalians under James Blair. It became a university in 1779. The se...

aerial and satellite photography

(Encyclopedia)aerial and satellite photography, technology and science of taking still or moving-picture photographs from a camera mounted on a balloon, airplane, satellite, rocket, or spacecraft. In the 19th cent....