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Geologic Timescale (table)

(Encyclopedia)Geologic Timescale 1 Not an era but the time preceding the Cambrian. ...

Canadian Shield

(Encyclopedia)Canadian Shield or Laurentian Plateau lôrĕnˈchən [key], U-shaped region of ancient rock, the nucleus of North America, stretching N from the Great Lakes to the Arctic Ocean. Covering more than hal...

Pliocene epoch

(Encyclopedia)Pliocene epoch plīˈəsēn [key], fifth epoch of the Cenozoic era of geologic time (see Geologic Timescale, tablegeologic timescale, table), from 5.1 to 2 million years ago. By the beginning of the P...

Oligocene epoch

(Encyclopedia)Oligocene epoch ŏlˈəgōsēnˌ [key], third epoch of the Tertiary period in the Cenozoic era of geologic time, lasting from 38 to 24 million years ago. More of North America was dry land during the ...

mammal

(Encyclopedia)mammal, an animal of the highest class of vertebrates, the Mammalia. The female has mammary glands, which secrete milk for the nourishment of the young after birth. In the majority of mammals the body...

Tertiary period

(Encyclopedia)Tertiary period tûrˈshēĕrˌē [key], name for the major portion of the Cenozoic era, the most recent of the geologic eras (see Geologic Timescale, tablegeologic timescale, table) from around 26 to...

Cretaceous period

(Encyclopedia)Cretaceous period krĭtāˈshəs [key], third and last period of the Mesozoic era of geologic time (see Geologic Timescale, tablegeologic timescale, table), lasting from approximately 144 to 65 millio...

reptile

(Encyclopedia)reptile, name for the dry-skinned, usually scaly, cold-blooded vertebrates (see Chordata) of the order Reptilia. Reptiles are found in a variety of habitats throughout the warm and temperate regions (...

Pleistocene epoch

(Encyclopedia)Pleistocene epoch plīˈstəsēn [key], 6th epoch of the Cenozoic era of geologic time (see Geologic Timescale, tablegeologic timescale, table). According to a classification that considered its depos...

Miocene epoch

(Encyclopedia)Miocene epoch mīˈəsēn [key], fourth epoch of the Tertiary period in the Cenozoic era of geologic time (see Geologic Timescale, tablegeologic timescale, table), lasting from around 24.6 to 5.1 mill...