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Pliocene epoch
Pliocene epoch , fifth epoch of the Cenozoic era of geologic time (see Geologic Timescale , table), from 5.1 to 2 million years ago. By the beginning of the Pliocene, the outlines of North America were almost the same as in recent time. Encroachments by the sea were limited to a narrow strip alon...
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Geologic Timescale
Geologic Timescale
Geologic Timescale
Era
Period
Epoch
Approximate duration (millions of years)
Approximate number of years ago (millions of years)
Not an era but the time preceding the Cambrian.
Cenozoic
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Tertiary period
Tertiary period , name for the major portion of the Cenozoic era , the most recent of the geologic eras (see Geologic Timescale , table) from around 26 to 66 million years ago. The name Tertiary was first applied about the middle of the 18th cent. to a layer of deposits, largely unconsolidated s...
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Tertiary period
Tertiary period , name for the major portion of the Cenozoic era , the most recent of the geologic eras (see Geologic Timescale , table) from around 26 to 66 million years ago. The name Tertiary was first applied about the middle of the 18th cent. to a layer of deposits, largely unconsolidated s...
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Sir Charles Lyell
Sir Charles Lyell , 1797-1875, British geologist. After studying and briefly practicing law, he spent most of his life in travel and in popularizing scientific ideas. He championed and won general acceptance of the theory of uniformity of causes, which was first proposed by James Hutton (as oppose...
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Cenozoic era
Cenozoic era , last major division of geologic time (see Geologic Timescale , table) lasting from 65 million years ago to the present. The Cenozoic is divided into the Tertiary (from 65 million years ago until 2 million years ago) and Quaternary (2 million years ago to the present) periods. Early i...
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Miocene epoch
Miocene epoch , fourth epoch of the Tertiary period in the Cenozoic era of geologic time (see Geologic Timescale , table), lasting from around 24.6 to 5.1 million years ago.
North America was more extensively submerged in the Miocene than in the preceding Oligocene epoch and underwent cons...
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horse
horse hoofed, herbivorous mammal now represented by a single extant genus, Equus. The term horse commonly refers only to the domestic Equus caballus and to the wild Przewalski's horse . (Other so-called wild horses are feral domestic horses or their descendants.) Adapted to plains environmen...
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Antarctica
Antarctica , the fifth largest continent, c.5,500,000 sq mi (14,245,000 sq km), asymmetrically centered on the South Pole and almost entirely within the Antarctic Circle.
Geology and Geography
Antarctica consists of two major regions: W Antarctica (c.2,500,000 sq mi/6,475,000 sq km), a mou...
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