Where: Ventura County, California (34.3° N, 118.7° W: paleocoordinates 35.1° N, 104.6° W)
• small collection-level geographic resolution
When: Llajas Formation, Lutetian (47.8 - 41.3 Ma)
• The stewart bed is a 1 m thick sandstone unit in the middle of the LLajas formation. Lutetian, chron 21r according to Squires (2001).
• bed-level stratigraphic resolution
Environment/lithology: transition zone or lower shoreface; bioturbated sandstone
• The "Stewart bed" is located in a section of transition from shallow-marine to outer slope and shelf facies. A nearshore environment is interpreted for that portion of the shallow-marine (transgressive) facies which consists of laminated beds alternating with bioturbated beds. In such cases, the finely laminated sand represents storm-influenced stratification, and the biogenic reworking is the inter-storm activity. Shell fragments commonly are concentrated as channel lags in surge channels. Fossils were apparently subjected to wave action because the apices of elongate shells such as Turritella are bimodally oriented in opposite directions. The deeper the water, the less amount of laminated sandstone and the more amount of bioturbated sandstone. Such areas, which were farther below effective wave base, existed 1) where the shallow-marine (transgressive) facies grades into the outer shelf to slope facies and 2) in the shallow-marine (regressive) facies. One of the deepest-water shallow-marine beds was the "Stewart bed."
Size class: macrofossils
Reposited in the LACM
Collection methods: bulk,
• Repository: Formerly California State University Northridge (CSUN)
Primary reference: R. L. Squires. 1983. New Mollusks from the Lower Middle Eocene Llajas Formation, Southern California. Journal of Paleontology 57(2):354-362 [L. Ivany/E. Kowalski/J. Marcot]more details
Purpose of describing collection: taxonomic analysis
PaleoDB collection 8013: authorized by Linda Ivany, entered by Elizabeth Kowalski on 12.06.2000, edited by Austin Hendy and Jonathan Marcot
Creative Commons license: CC BY (attribution)
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