Locality 13, Round Hill, Symphysurina beds (Ordovician of the United States)

Where: Box Elder County, Utah (41.5° N, 111.9° W: paleocoordinates 7.2° S, 82.4° W)

• coordinate estimated from map

• local area-level geographic resolution

When: Symphysurina bulbosa trilobite zone, Garden City Formation, Gasconadian (485.4 - 477.7 Ma)

• Fossils collected at base of 283 foot interval beginning at 90 feet above base of formation. Check to make sure this is not latest Cambrian!

• group of beds-level stratigraphic resolution

Environment/lithology: shallow subtidal; lithified, fine-grained limestone and lithified conglomerate

• "Thick, 3- to 4-foot interbeds of finely crystalline limestone, intraformational conglomerate, shaly limestone, and aphanitic limestone."

Size class: macrofossils

Collected by R. J. Ross, Jr. in 1946-1947; reposited in the YPM

Primary reference: R. J., J.r. Ross. 1951. Stratigraphy of the Garden City Formation in northeastern Utah, and its trilobite faunas. Yale Peabody Museum of Natural History Bulletin 6:1-161 [S. Finnegan/S. Finnegan/P. Wagner]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 103920: authorized by Melanie Hopkins, entered by Melanie Hopkins on 03.02.2011

Creative Commons license: CC BY (attribution)

Taxonomic list

• Description in measured section states that this interval contained a "complete trilobite assemblage from Zone 'J'" (p. 23). Taxonomic list taken from faunal list on p. 27-28.
Show authors, comments, and common names
Rhynchonellata
 Orthida - Plectorthidae
Nanorthis sp.
Nanorthis sp. Ulrich and Cooper 1936
 Pentamerida - Clarkellidae
? Syntrophina sp.
Trilobita
 Asaphida - Nileidae
Symphysurina sp.
Symphysurina sp. Ulrich 1924 trilobite
 Proetida - Hystricuridae
Hystricurus "sp. E"
Hystricurus "sp. E" Raymond 1913 trilobite