Irvingtonian

The Irvingtonian North American Stage on the geologic timescale is the North American faunal stage

Faunal stage

In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convention have the same name, and the same boundaries.Rock...

 according to the North American Land Mammal Ages

North American Land Mammal Ages

The North American Mammal Ages establishes a geologic timescale for prehistoric North American fauna beginning 66.5 Ma during the Paleocene and continuing through to the Late Pleistocene...

 chronology (NALMA), typically set from 1,800,000 to 300,000 years BP

Before Present

Before Present years is a time scale used in archaeology, geology, and other scientific disciplines to specify when events in the past occurred. Because the "present" time changes, standard practice is to use AD 1950 as the origin of the age scale, reflecting the fact that radiocarbon...

, a period of . It is usually considered to overlap the Lower Pleistocene and Middle Pleistocene

Middle Pleistocene

The Middle Pleistocene, more specifically referred to as the Ionian stage, is a period of geologic time from ca. 781 to 126 thousand years ago....

 epochs. The Irvingtonian is preceded by the Blancan

Blancan

The Blancan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology , typically set from 4,750,000 to 1,808,000 years BP, a period of .. It is usually considered to start in the early-mid Pliocene epoch and end...

 and followed by the Rancholabrean

Rancholabrean

The Rancholabrean North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology , typically set from less than 240,000 years to 11,000 years BP, a period of . It is usually considered to overlap the Middle Pleistocene...

NALMA stages.

The Irvingtonian can be further divided into the substages of:

• Cudahyan: Lower boundary source: base of Irvingtonian (approximate)
• Sappan: Upper boundary source: base of Rancholabrean (approximate)