Gomphocystites Assoc., Farmers Creek Member, Hopkinton Fm., Eastern Iowa (Silurian of the United States)

Where: Iowa (42.5° N, 91.5° W)

• Paleocoordinates: 26.1° S, 106.3° W (Wright 2013)

• coordinate estimated from map

• local area-level geographic resolution

When: Farmers Creek Member (Hopkinton Formation), Llandovery (443.4 - 433.4 Ma)

• Late Llandovery (C4). Middle and lower F.C. Member.

• member-level stratigraphic resolution

Environment/lithology: deep subtidal ramp; dolomitic, shelly/skeletal grainstone and dolomitic, shelly/skeletal packstone

• "Echinoderm thecae intact, but never retain the subvective appendages...Witzke (1983) interprets the middle F.c. as BA 3-4; the echioderm comm. is most likely outer BA3 to shallow BA 4. The near total locak of other shelly benthic groups is unusual for communities of this age and lithology..." Community is in the general Shoal/Mound Association Group.

•

•SEP environmental call based on given description and same vol. page 807.

• "The most common lithology is very fine-grained, porous, noncherty, flat-lying dolograinstone to dolopackstone."

Collection methods: Echinoderm abundances given in table 45.24.

Primary reference: T. J. Frest, C. E. Brett, and B. J. Witzke. 1999. Caradocian-Gedinnian echinoderm associations of Central and Eastern North America. Paleocommunities--a case study from the Silurian and Lower Devonian 638-783 [M. Foote/K. Koverman/P. Wagner]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 26714: authorized by Michael Foote, entered by Michael Foote on 25.10.2002

Creative Commons license: CC0 (CC0)

Taxonomic list

Show authors, comments, and common names
Crinoidea
 Monobathrida - Marsupiocrinidae
Marsupiocrinus (Amarsupiocrinus) primaevus
 Monobathrida - Patelliocrinidae
Macrostylocrinus "sp. E Witzke and Strimple"
 Glyptosphaeritida - Gomphocystitidae
Gomphocystites sp.
Gastropoda
  -
Gastropoda indet.
Gastropoda indet. Cuvier 1795 snail
Rhynchonellata
 Spiriferida - Cyrtiidae
Hedeina sp.
Hedeina sp. Boucot 1957
 Athyridida - Meristellidae
? Meristina sp.
? Meristina sp. Hall 1867
 Atrypida - Atrypidae
Atrypa "reticularis"
Atrypa "reticularis" Linnaeus 1758
 Rhynchonellida -
Rhynchonellida indet.