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Emigrant Springs Formation

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Not to be confused with the Emigrant Formation, a different formation of a similar age.
Emigrant Springs Formation
Stratigraphic range: Middle Cambrian–Upper Cambrian [1]
TypeFormation
Sub-unitsSee: Members
UnderliesDunderberg Formation
OverliesPatterson Pass Shale
Lithology
PrimaryCalcisiltite
OtherMudstone, Calcilutite, Calcarenite
Location
RegionNevada
CountryUnited States

The Emigrant Springs Formation (Also known as the Emigrant Springs Limestone) is a geologic formation in Nevada. It preserves fossils dating back to the Cambrian period.

Geology

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The Emigrant Springs Formation contains three members, which are as follows, in ascending age:

Members

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  • Member A: This member is the thinnest, only getting up to 256 ft (78 m) thick, and is composed of medium-gray, thin to medium-bedded calcisiltite and calcilutite, with breccia's in the upper beds of the member.[1]
  • Member B: This member is the thickest, getting up to 1,509 ft (460 m) thick, and is dominated by light-olive-gray, yellowish or pink calcisiltite, which contains silt-sized quartz grains. At the base of this member, there are also mudstones present, transitioning to medium-light-gray, thin to thick-bedded calcisiltite and calcilutite above.[1]
  • Member C: This member can get up to 495 ft (151 m) thick, and is primarily composed of medium-gray oolitic calcarenite, calcilutite and calcisiltite.[1]

Paleobiota

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The Emigrant Springs Formation contains a small number of trilobites,[1] and a collection of conodonts, and various molluscs.[2]

Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Arthropoda

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Arthropoda
Genus Species Notes Images
Coosina[1]
  • Coosina sp.
 Ptychoparid trilobite.
Blountia[1]
  • Blountia sp.
 Ptychoparid trilobite.
Crepicephalus[1]
  • Crepicephalus sp.
 Ptychoparid trilobite.
Tricrepicephalus[1]
  • Crepicephalus sp.
 Ptychoparid trilobite.
Pemphigaspis[1]
  • Pemphigaspis sp.
 Ptychoparid trilobite.
Elrathia[2]
  • E. alapyge
 Ptychoparid trilobite.
Cedaria (?)[1]
  • Cedaria (?) sp.
 Ptychoparid trilobite.
Meteoraspis (?)[1]
  • Meteoraspis (?) sp.
 Ptychoparid trilobite.
Baltagnostus[2]
  • Baltagnostus sp.
  • B. eurypyx
 Diplagnostid agnostid.
Hypagnostus[2]
  • Hypagnostus sp.
 Diplagnostid agnostid.
Pseudagnostus[1]
  • Pseudagnostus sp.
 Agnostid trilobite.
Utagnostus[1]
  • U. trispinulus
 Agnostid trilobite.
Kymagnostus (?)[1]
  • Kymagnostus (?) sp.
 Agnostid trilobite.
Lejopyge[2][1]
  • L. calva
Ptychagnostid agnostid.
Ptychagnostus[2]
  • Ptychagnostus sp.
  • P. aculeatus
 Ptychagnostid agnostid.
Glaphyraspis[1]
  • Glaphyraspis sp.
 Trilobite.
Cheliacephalus[1]
  • Cheliacephalus sp.
 Trilobite.
Aphelaspis[1]
  • Aphelaspis sp.
 Trilobite.

Chordata

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Genus Species Notes Images
Hertzina[2]
  • H. bisulcata
 Furnishinid paraconodont.
Westergaardodina[2]
  • W. muelleri
 Westergaardodinid paraconodont.
Furnishina[2]
  • F. asymmetrica
  • F. furnishi
  • F. bicarinata
 Furnishinid paraconodont.
Distacodus[2]
  • D. palmeri
 Distacodontid conodont.
Oneotodus[2]
  • O. tenuis
 Protopanderodontid tenuis.

Lophotrochozoa

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Genus Species Notes Images
Helcionella[2]
  • Helcionella sp.
 Helcionellid mollusc.
Scenella (?)[2]
  • Scenella (?) sp.
 Scenellid mollusc.
Canthylotreta[3]
  • C. crista
 Acrotretid brachiopod.
Lingulella[2]
  • Lingulella sp.
 Obolid brachiopod.
Livnarssonia[2]
  • L. ophirensis
 Brachiopod.
Paterina[2]
  • Paterina sp.
 Brachiopod.

See also

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References

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  1. ^ a b c d e f g h i j k l m n o p q r s Kellogg, Harold E. (1963). "Paleozoic Stratigraphy of the Southern Egan Range, Nevada". Geological Society of America Bulletin. 74 (6): 685. doi:10.1130/0016-7606(1963)74[685:PSOTSE]2.0.CO;2.
  2. ^ a b c d e f g h i j k l m n o p Clark, David L.; Robison, Richard A. (1969). "Oldest Conodonts in North America". Journal of Paleontology. 43 (4): 1044–1046. ISSN 0022-3360.
  3. ^ Streng, Michael; Holmer, Lars E. (January 2006). "New and poorly known acrotretid brachiopods (Class Lingulata) from the Cedaria-Crepicephalus zone (late Middle Cambrian) of the Great Basin, USA". Geobios. 39 (1): 125–154. doi:10.1016/j.geobios.2004.10.004.


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