Fremont Massive Dolomite (Ordovician to of the United States)

Where: Colorado (38.0° N, 105.0° W: paleocoordinates 15.0° S, 71.2° W)

• local area-level geographic resolution

When: Amorphognathus superbus conodont zone, Massive Dolomite Member (Fremont Formation), Maysvillian to Maysvillian (450.2 - 445.5 Ma)

• Massive Dolomite portion that should be it's own Member. (PJW transcribing!)

• member-level stratigraphic resolution

Environment/lithology: shallow subtidal; lithified, red, cherty/siliceous dolomite

• Environment, tectonic setting, and modes of preservation from S. Holland.
• Dolomite, cherty, massive, gray-buff, pinkish, reddish, finely to coarsely crystalline, deeply weathered at base.

Size class: macrofossils

Preservation: original calcite, replaced with calcite, replaced with silica

Primary reference: W. C. Sweet. 1954. Harding and Fremont Formations, Colorado. Bulletin of the American Association of Petroleum Geologists 38(2):284-305 [S. Holland/T. Hanson]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 10338: authorized by Steven Holland, entered by Tori Hanson on 04.04.2001

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Chlorophyceae
  - Receptaculitidae
Receptaculites cf. articus
Anthozoa
 Heliolitida - Halysitidae
"Halysites cf. robustus" = Catenipora robusta, "Halysites cf. delicatulus" = Catenipora delicatulus
"Halysites cf. robustus" = Catenipora robusta Wilson 1926 tabulate coral
"Halysites cf. delicatulus" = Catenipora delicatulus Wilson 1926 tabulate coral
 Sarcinulida - Syringophyllidae
Calapoecia sp.
Calapoecia sp. Billings 1865 tabulate coral
 Stauriida - Streptelasmatidae
Streptelasma sp.
Streptelasma sp. Hall 1847 horn coral
 Rhombifera - Echinosphaeritidae
? Echinosphaerites sp.
? Echinosphaerites sp. Wahlenberg 1818
Crinoidea
  -
Crinoidea indet.
Crinoidea indet. Miller 1821 Sea lily
Rhynchonellata
 Rhynchonellida - Rhynchotrematidae
"Rhynchotrema argenturbicum" = Hypsiptycha argenturbicum
"Rhynchotrema argenturbicum" = Hypsiptycha argenturbicum White 1874
Lepidocyclus?
 Orthida - Plaesiomyidae
Plaesiomys bellilamellosus
Strophomenata
 Strophomenida - Strophomenidae
Strophomena spp.
Strophomena spp. Rafinesque and De Blainville 1824
Cephalopoda
 Pseudorthocerida - Spyroceratidae
Spyroceras sp.
Spyroceras sp. Hyatt 1884
 Ascocerida - Probillingsitidae
Probillingsites sp.
Probillingsites sp. Foerste 1928
 Oncocerida - Oncoceratidae
Beloitoceras sp., Neumatoceras sp.
Beloitoceras sp. Foerste 1924
Neumatoceras sp. Foerste 1935
 Actinocerida - Actinoceratidae
Actinoceras sp.
Actinoceras sp. Bronn 1837
 Actinocerida - Gonioceratidae
Lambeoceras sp.
Lambeoceras sp. Foerste 1917
 Orthocerida - Proteoceratidae
Ephippiorthoceras spp.
 Orthocerida - Kionoceratidae
Kionoceras sp.
Kionoceras sp. Hyatt 1884
 Endocerida - Endoceratidae
Endoceras spp., Cyclendoceras sp.
Endoceras spp. Hall 1847
Cyclendoceras sp. Grabau and Shimer 1910
Gastropoda
 Bellerophontida - Bucanellidae
Bucanella sp.
Bucanella sp. Meek 1871 snail
 Euomphalina - Helicotomidae
Helicotoma sp.
Helicotoma sp. Salter 1859 snail
 Murchisoniina - Trochonematidae
"Trochonema umbilicatum" = Trochonema umbilicata
"Trochonema umbilicatum" = Trochonema umbilicata Hall 1847 snail