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| rich soil containing a relatively equal mixture of sand, silt and a smaller proportion of clay |
| central portion of the earth believed to be composed mainly of iron and nickel in a molten state |
| Cenozoic (sěn'ə-zō'ĭk) Pronunciation Key
The most recent era of geologic time, from about 65 million years ago to the present. The Cenozoic Era is characterized by the formation of modern continents and the diversification of mammals and plants. Grasses also evolved during the Cenozoic. The climate was warm and tropical toward the beginning of the era and cooled significantly in the second half, leading to several ice ages. Humans first appeared near the end of this era. See Chart at geologic time. |