The Neogene is not part of the Quaternary. The Neogene is a geologic period that lasted from 23.03 million years ago to 2.58 million years ago, and it is the most recent period of the Cenozoic Era. The Quaternary is the current and youngest geologic period, which started 2.58 million years ago and continues to the present day. The Quaternary is composed of two epochs, the Pleistocene and the Holocene. The Pleistocene epoch lasted from 2.58 million years ago to 11,700 years ago, and it was characterized by repeated cycles of glaciation and deglaciation. The Holocene epoch began 11,700 years ago and continues to the present day, and it is characterized by a relatively stable climate.