Crill Coal Bed (Cretaceous of the United States)

Also known as Coal bed located near the site of the old Crill mill at a point where the Big Sioux River has cut away the gravel plain at the the base of a bluff, Plymouth County, Iowa (Dakota Group)

Where: Plymouth County, Iowa (42.7° N, 96.5° W: paleocoordinates 40.5° N, 57.9° W)

• coordinate estimated from map

• outcrop-level geographic resolution

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

• This section of Crill coal is overlain by the Granerose and Greenhorn formations of the Colorado Group in this area.

Environment/lithology: mire or swamp; coal

• Tester (1929) concludes that the type area of the Dakota stage \"represents the sediments laid down in an environment at and near the shore line of a broad, relatively shallow ocean. The material was derived from the north and northeast and was carried southward by streams of small competency which may have had wide flood plains and which when reaching the coast line built wide and ramifying deltas."
• The Crill coal is approximately 1.2 ft. thick where the samples were taken. IT is overlain by approximately 15 ft. of sandstone and underlain by fire clay to the water line.

Size class: microfossils

Preservation: original sporopollenin

Collection methods: surface (float), chemical,

• The plant microfossils were liberated for study by a maceration process essentially the same as that described by Wilson and Webster (1946). All types and figured specimens are deposited at the Museum of Paleontology of the University of Michigan.

Primary reference: M. P. Schemel. 1950. Cretaceous Plant Microfossils from Iowa. American Journal of Botany 37(9):750-754 [R. Lupia/T. Naeher/T. Naeher]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 32479: authorized by Rick Lupia, entered by Tiffany Naeher on 03.07.2003

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Polypodiopsida
  - Marsileaceae
Molaspora rugosa n. gen. n. sp.
Molaspora rugosa n. gen. n. sp.
Pteridopsida
 Marsileales -
Arcellites crillensis n. sp.
Jungermanniopsida
 Jungermanniales - Jungermaniidae
Chrysotheca dakotaensis n. sp.
Spermatites
  -
Spermatites ellipticus, Spermatites sp.
Spermatites sp. Miner 1935
Spermatites elongatus
  -
Spermatites elongatus