Fig. 3. Simplified stratigraphic log showing main Early Triassic fossil-bearing levels currently known in the Bear Lake area.

Fossil occurrence is modified following the study by Romano et al. (57), with additional data from studies by Massare and Callaway (58) (ichthyosaur remains), Tosk and Andersson (59) (foraminifers), and Hofmann et al. (60) and from our own field observations (black stars). Conodonts are also sparsely present throughout the section but are not represented here. Stratigraphy follows the main units defined by Kummel (61, 62). Zonation is based on ammonoids (20, 54, 55, 62, 63). Position of the Paris Biota is highlighted in red. A U-Pb age of 250.55 ± 0.4 My is associated with the Tirolites/Columbites beds from South China (5). LL, Lower Limestone; LS, Lower Shale; ML, Middle Limestone; MS, Middle Shale; UCS, Upper Calcareous Siltstone; Meek, Meekoceras beds; Anasib, Anasibirites beds; Tirol, Tirolites beds; Colum, Columbites beds.