Also known as Samples from some 50 feet above the Missouri River, a few miles south of Sioux City, Iowa (Dakota Formation)

Where: Woodbury County, Iowa (42.5° N, 96.4° W: paleocoordinates 40.4° N, 57.9° W)

• coordinate based on political unit

• outcrop-level geographic resolution

When: Dakota Formation, Cenomanian (100.5 - 93.9 Ma)

• These samples come from some 50 feet above the Missouri River, a few miles south of Sioux City, Iowa.

Environment/lithology:

Size class: microfossils

Preservation: original sporopollenin

Collection methods: surface (in situ), chemical, sieve,

• A sample of about 100 grams was washed through a coarse sieve and then through a 100 mesh sieve. The residue was treated with hot 5% NaOH for 5 minutes or cold NaOH overnight and wasshed thoroughly. Some samples were then suspended in ZnCl2 of high specific gravity and centrifuged, for removal of mineral particles. Some samples were also bleached in acidified Clorox for varying periods, up to 30 minutes, and washed thoroughly; bleaching aided immeasurably in finding the spores. After these separation techniques, the spores were simply picked out by hand, as no method was found which would separate mechanically the spores from the very abundant cuticular fragments and the remaining bits of fusainized wood.

Primary reference: J. W. Hall. 1963. Megaspores and other fossils in the Dakota Formation (Cenomanian) of Iowa, (U.S.A.). Pollen et Spores 5(2):425-443 [R. Lupia/T. Naeher/T. Naeher]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 32524: authorized by Rick Lupia, entered by Tiffany Naeher on 08.07.2003

Creative Commons license: CC BY (attribution)