ABSTRACT: The Claron Formation is a well-known lithologic unit located in southwestern Utah (USA) that forms extraordinary cliffs such as those of Cedar Breaks NationalMonument and the Bryce Canyon National Park. The relative age of Claron Formation is a controversial topic due to its lithological characteristics, i.e. diagenesis and the low fossils abundance. Acharophyte assemblage located at the Griffin Top section (Aquarius Plateau, Utah, USA) provides, for the first time, the relative age of the base of the Claron Formation. A well-preserved population of charophytes belonging to Peckichara torulosa (Dollfus and Fritel, 1919) Grambast, 1957 is described from the lower pink member of the Claron Formation. Based on documented ages of this charophyte species in Europe andChina, we infer that the basal part of the Claron Formation is lower Eocene in age (Ypresian).