The
Cretaceous, derived from the
Latin "creta", usually abbreviated
K for its
German translation Kreide, is a
geologic period and system from circa
145.5 ± 4 to
65.5 ± 0.3 million years ago. In the
geologic timescale, the Cretaceous follows the
Jurassic period and is followed by the
Paleogene period of the
Cenozoic era. It is the youngest period of the
Mesozoic era, and at 80 million years long, the longest period of the
Phanerozoic Eon. The end of the Cretaceous defines the boundary between the Mesozoic and
Cenozoic eras. In many languages this period is known as "chalk period".