1. An age in the Middle Eocene, preceded by the Ypresian (Early Eocene), followed by the Bartonian, and with a lower boundary dated at 50.0 Ma ( Harland et al., 1989).
2. The name of the corresponding European stage, which is roughly contemporaneous with the upper Ulatizian and lower Narizian (N. America), the upper Heretaungan, Porangan, and lower Bortonian (New Zealand), and the upper Johannian and lower Aldingan (Australia).
"Lutetian." A Dictionary of Earth Sciences. . Encyclopedia.com. (September 23, 2018). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/lutetian
"Lutetian." A Dictionary of Earth Sciences. . Retrieved September 23, 2018 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/lutetian