Ypresian

In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between 55.8±0.2 and 48.6±0.2 Ma, is preceded by the Thanetian age (part of the Paleocene) and is followed by the Eocene Lutetian age.

The Ypresian is sometimes included with the Lutetian in an Early Eocene subepoch.