ammonites
Scaphiocoelia Zone trilobites, Lower Belen Fmn., Belen-La Paz-Sicasica region (Devonian of Bolivia)

Where: La Paz, Bolivia (17.0° S, 68.0° W: paleocoordinates 63.5° S, 88.1° W)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Lower Belen Member (Belen Formation), Emsian (409.1 - 391.9 Ma)

• Scaphiocoelia Zone well recognized. Emsian age follows Isaacson (ref. 9680).

• member-level stratigraphic resolution

Environment/lithology: marine; micaceous, gray siltstone and micaceous, gray mudstone

• Isaacson (ref. 9681) interprets Scaph.-zone units as BA 2 in intracratonic basin, and succeeding units as deeper.
• From Isaacson (ref. 9681): "The lower quarter of [Lower Belen] is siltstone. Fresh surfaces gray to greenish, weathered surfaces brown...siltstone very micaceous...half-way through the unit are symmetrical ripple marks...The next half of the Lower Belen is a [gray] mudstone [micaceous]. Upper quarter of Lower Belen at Belen is a seq. of variable lithology. Predominating is siltstone, with fine-grained sandstone and mudstone appearing in interbeds...gray...[micaceous]"

Primary reference: N. Eldredge and L. Branisa. 1980. Calmoniid trilobites of the Lower Devonian Scaphiocoelia Zone of Bolivia, with remarks on related species. Bulletin of the American Museum of Natural History 165(2):181-289 [M. Foote/M. Foote/M. Foote] more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 36133: authorized by Michael Foote, entered by Michael Foote on 14.01.2004