Where: Idaho (42.5° N, 111.4° W: paleocoordinates 11.9° N, 35.3° W)

• coordinate estimated from map

• local area-level geographic resolution

When: Lower Shale Member, Spathian (251.3 - 247.2 Ma)

• The exposures dip gently northward and their combined thickness reaches ~20 m. They are located below the Spathian Middle Limestone unit and overlie the Smithian Lower Limestone unit. However, the contact with the Lower Limestone unit is not visible in this area. The occurrence of the ammonoid species Tirolites harti indicates an early Spathian age for the Middle Limestone unit. This unit is coeval or slightly older than the Tirolites/Columbites beds of South China, which yield a radiometric age of ~250.55 ± 0.4 Ma. Abundant Tirolites specimens are also reported here for the first time from the upper part of the underlying Lower Shale unit where the Paris Biota occurs; unfortunately, their compressed preservation prevents a firm species assignment. However, the genus determination is easy and robust enough to confirm an earliest Spathian age for this biota as this genus is found worldwide in this time interval only. Tirolites specimens are found throughout the four studied exposures of the upper part of the Lower Shale unit, confirming their earliest Spathian age.

• group of beds-level stratigraphic resolution

Environment/lithology: transition zone or lower shoreface; lithified, silty mudstone and lithified marl

Size classes: macrofossils, mesofossils

Preservation: mold/impression

Collection methods: Repository: Université de Bourgogne, Géologie Dijon, France

Primary reference: S. Charbonnier, A. Brayard, and T. Paris Biota Team. 2019. New thylacocephalans from the Early Triassic Paris Biota (Bear Lake County, Idaho, USA). Geobios 54:37-43 [M. Clapham/M. Clapham/M. Clapham]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 202191: authorized by Matthew Clapham, entered by Matthew Clapham on 28.06.2019

Creative Commons license: CC BY (attribution)