Emigrant Springs Formation

Emigrant Springs Formation
Emigrant Springs Formation
Stratigraphic range: Middle Cambrian–Upper Cambrian PreꞒ Ꞓ O S D C P T J K Pg N
Type	Formation
Sub-units	See: Members
Underlies	Dunderberg Formation
Overlies	Patterson Pass Shale
Lithology
Primary	Calcisiltite
Other	Mudstone, Calcilutite, Calcarenite
Location
Region	Nevada
Country	United States

Last updated December 16, 2025

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

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

Members

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

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

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

Genus	Species	Notes
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

Genus	Species	Notes
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.

References

Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Archived from the original on 25 March 2022. Retrieved 8 July 2014.

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 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.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Clark, David L.; Robison, Richard A. (1969). "Oldest Conodonts in North America". Journal of Paleontology. 43 (4): 1044–1046. ISSN 0022-3360.
↑ 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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[Kellogg1963-1] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 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.

[Clark1959-2] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Clark, David L.; Robison, Richard A. (1969). "Oldest Conodonts in North America". Journal of Paleontology. 43 (4): 1044–1046. ISSN 0022-3360.

[Streng2006-3] 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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