Mule Spring Limestone

Mule Spring Limestone
Mule Spring Limestone
Stratigraphic range: Lower Cambrian PreꞒ Ꞓ O S D C P T J K Pg N
Type	Formation
Underlies	Monola Formation (Saline Range); Emigrant Formation (Split Mountain);
Overlies	Saline Valley Formation (Saline Range); Harkless Formation (Split Mountain);
Thickness	0–1,000 feet (0–305 m)
Lithology
Primary	Limestone
Other	Siltstone, Shale,
Location
Region	Mojave Desert, California, Nevada
Country	United States

The Mule Spring Limestone is a geologic formation in the Saline Range of eastern California and Split Mountain and Goldfield Hills of Nevada. It can also be found outcropping in the Inyo Mountains and White Mountains.

The formation also preserves fossils, primarily trilobites, dating back to the Cambrian period.

Geology

The Mule Spring Limestone, as its name suggests, is mainly composed of limestone rocks. These rocks are medium-gray to light-medium-gray, as well as very fine to fine crystalline, and is thin to very thin-bedded in most areas. In the lower sections of the formation, there are also occasional layers, up to 500 ft (150 m) thick, of pale-yellowish-brown or greenish-gray shale, limy siltstone and silty limestone.^[1] In the Split Mountain, the formation overlies the Harkless Formation and underlies the Emigrant Formation,^[1]^[2] whilst in other areas it overlies the Saline Valley Formation and underlies the Monola Formation.^[1]

Paleobiota

The Mule Spring Limestone contains examples of Archaeocyatha, a clade of sponges that went extinct during this time,^[3] as well as a collection of trilobites.^[4]^[1]

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

Genus	Species	Notes
Bristolia^[1]^[4]^[5]^[2]	Bristolia sp. B. harringtoni B. insolens B. bristolensis B. anteros B. fragilis	Biceratopsid trilobites.
Peachella^[1]^[4]^[5]	Peachella sp.	Biceratopsid trilobite.
Mesonacis^[4]	Mesonacis sp.	Olenellid trilobite. Mesonacis sp. previously described as Fremontia sp. which was later synonymised into Mesonacis.^[1]
Olenellus^[4]^[5]^[6]^[2]	Olenellus sp. O. puertoblancoensis(?)	Olenellid trilobite. Olenellus sp. previously described as Paedumias sp. which was later synonymised into Olenellus.^[1]
Onchocephalus^[4]^[5]	Onchocephalus sp.	Ptychoparid trilobite.
Ptychoparioid^[4]^[6]^[2]	Ptychoparioid sp. A Ptychoparioid sp. B Ptychoparioid sp. C Ptychoparioid sp. D	Ptychoparid trilobites.
Bonnia^[1]^[4]^[5]^[2]	Bonnia sp.	Dorypygid trilobite.
Crassifimbra^[2]	Crassifimbra sp.	Trilobite, family unknown.

Porifera (Sponges)

Genus	Species	Notes	Images
Archaeocyathus^[3]	Archaeocyathus sp.	Archaeocyathide sponge.

Flora

Genus	Species	Notes	Images
Girvanella^[1]	Girvanella sp.	Cyanobacteria structures.

References

1 2 3 4 5 6 7 8 9 10 11 12 Stewart, J. H. "Upper Precambrian and Lower Cambrian Strata, in the Southern Great Basin California and Nevada" (PDF). U.S. Geological Survery. Geological Survey Professional.
1 2 3 4 5 6 Sundberg, Frederick A.; Webster, Mark (July 2022). ""Ptychoparioid" trilobites of the Harkless Formation and Mule Spring Limestone (Cambrian Series 2, Stage 4), Clayton Ridge, Nevada". Journal of Paleontology. 96 (4): 886–920. doi:10.1017/jpa.2021.124.
1 2 Pruss, Sara B.; Karbowski, Grace; Zhuravlev, Andrey Yu; Webster, Mark; Smith, Emily F. (30 June 2024). "DEAD CLADE WALKING: THE PERSISTENCE OF ARCHAEOCYATHUS IN THE AFTERMATH OF EARLY CAMBRIAN REEF EXTINCTION IN THE WESTERN UNITED STATES". Palaios. 39 (6): 210–224. doi:10.2110/palo.2024.005.
1 2 3 4 5 6 7 8 Mule Spring Limestone Formation Trilobites
1 2 3 4 5 Alpert, Stephen P. (1976). "Trilobite and Star-like Trace Fossils from the White-Inyo Mountains, California". Journal of Paleontology. 50 (2): 226–239. ISSN 0022-3360.
1 2 Sundberg, Frederick A.; McCollum, Linda B. (September 2003). "Early and Mid Cambrian trilobites from the outer‐shelf deposits of Nevada and California, USA". Palaeontology. 46 (5): 945–986. doi:10.1111/1475-4983.00328.

Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Retrieved 17 December 2021.

[Stewart1970-1] 1 2 3 4 5 6 7 8 9 10 11 12 Stewart, J. H. "Upper Precambrian and Lower Cambrian Strata, in the Southern Great Basin California and Nevada" (PDF). U.S. Geological Survery. Geological Survey Professional.

[Sundberg2022-2] 1 2 3 4 5 6 Sundberg, Frederick A.; Webster, Mark (July 2022). ""Ptychoparioid" trilobites of the Harkless Formation and Mule Spring Limestone (Cambrian Series 2, Stage 4), Clayton Ridge, Nevada". Journal of Paleontology. 96 (4): 886–920. doi:10.1017/jpa.2021.124.

[Pruss2024-3] 1 2 Pruss, Sara B.; Karbowski, Grace; Zhuravlev, Andrey Yu; Webster, Mark; Smith, Emily F. (30 June 2024). "DEAD CLADE WALKING: THE PERSISTENCE OF ARCHAEOCYATHUS IN THE AFTERMATH OF EARLY CAMBRIAN REEF EXTINCTION IN THE WESTERN UNITED STATES". Palaios. 39 (6): 210–224. doi:10.2110/palo.2024.005.

[MuleTrilos-4] 1 2 3 4 5 6 7 8 Mule Spring Limestone Formation Trilobites

[Alpert1976-5] 1 2 3 4 5 Alpert, Stephen P. (1976). "Trilobite and Star-like Trace Fossils from the White-Inyo Mountains, California". Journal of Paleontology. 50 (2): 226–239. ISSN 0022-3360.

[Sundberg2003-6] 1 2 Sundberg, Frederick A.; McCollum, Linda B. (September 2003). "Early and Mid Cambrian trilobites from the outer‐shelf deposits of Nevada and California, USA". Palaeontology. 46 (5): 945–986. doi:10.1111/1475-4983.00328.

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