Emigrant Formation

Members

The formation contains three members, which are as follows, in ascending age:

• Limestone & Siltstone Member: This member is the thinnest of the three, only getting up to 150 m (490 ft) thick in some areas, and is dominated by lime mudstone. At the base of the member, it is entirely composed of shale, which gives way to calcareous sandstone, and then the common lime mudstones above that. Within these lime mudstones, there are occasional layers of more shale and chert.^[1]
• Shale Member: This member can get up to 250 m (820 ft) thick in some areas, and is, as the name suggests, entirely dominated by shale, which may be faulted and repeated in many places.^[1]
• Limestone & Chert Member: This member is the thickest of the three, getting up to 300 m (980 ft) thick in some areas, and contains a mixture of ribbon limestone, inter-bedded shales, as well as mega-breccia.^[1]

The Emigrant Formation also contains lower Ordovician aged rocks above the Limestone & Chert Member, informally known as the "Platy Limestone Unit". This unit is primarily composed of fine-grained, platy limestone, which are inter-bedded with pale-red siltstone. The very top of the unit is not preserved, and contacts the overlying Palmetto Formation at a fault, and the unit itself is also difficult to age, although a lower Ordovician age is suggested, though more evidence will be needed to pinpoint the exact age of the unit. It has also been noted that this unit may represent a transitional bed between the Emigrant and Palmetto Formations.^[2]

Cambrian

This section details all the fossils from the Cambrian sections of the Emigrant formation.

Arthropoda

More information Arthropoda, Genus ...

Arthropoda
Genus	Species	Notes	Images
Amecephalus[3]	Amecephalus (?) sp. A. arrojosensis	Ptychoparid trilobite.
Mexicella[3]	M. robusta	Ptychoparid trilobite.
Paraantagmus[3]	P. latus	Ptychoparid trilobite.
Onchocephalites[3]	Onchocephalites sp. O. claytonensis O. runcinatus	Ptychoparid trilobite.
Tonopahella[3]	T. goldfieldensis	Ptychoparid trilobite.
Syspacephalus[3][5]	S. variosus S. laticeps S. mccollumorum	Ptychoparid trilobite.
Achlysopsis[5]	A. brighamensis A. liokata	Ptychoparid trilobite.
Eokochaspis[3]	E. nodosa E. delamarensis (?) E. piochensis (?) E. longspina (?)	Ptychoparid trilobite.
Chancia[5]	C. maladensis	Ptychoparid trilobite.
Kistocare[5]	Kistocare sp.	Ptychoparid trilobite.
Elrathia[5]	E. marginalis	Ptychoparid trilobite.
Alokistocare[5]	A. paranotatum	Ptychoparid trilobite.
Meteoraspis[5]	Meteoraspis sp.	Ptychoparid trilobite.
Coosella[5]	Coosella sp.	Ptychoparid trilobite.
Coosia[5]	Coosia sp.	Ptychoparid trilobite.
Crepicephalus[5]	Crepicephalus sp.	Ptychoparid trilobite.
Tricrepicephalusalus[5]	Tricrepicephalus sp.	Ptychoparid trilobite.
Cedaria[5]	Cedaria sp. 1 Cedaria sp. 2 C. selwyni C. brevifrons	Ptychoparid trilobite.
Utia (?)[5]	U. curio (?)	Ptychoparid trilobite.
Kochaspid (?)[3]	Kochaspid (?) sp.	Ptychoparid trilobite.
Ptychoparioid[3][5]	Ptychoparioid sp. A Ptychoparioid sp. B	Ptychoparid trilobites.
Oryctocephalus[3][5]	Oryctocephalus sp. A O. americanus O. minor O. orientalus O. indicus O. maior O. reynoldsi	Corynexochid trilobite.
Euarthricocephalus[5]	E. nevadensis E. (?) wheelera	Corynexochid trilobite.
Ovatoryctocara[3][5]	O. sinensis Oryctocephalus (?) sp.	Corynexochid trilobite.
Glossopleura[5]	G. walcotti	Corynexochid trilobite.
Zacanthoides[5]	Zacanthoides sp. Z. longipgus Z. divergens	Corynexochid trilobite.
Thoracocare[5]	T. minuta	Corynexochid trilobite.
Parkaspis[5]	P. drumensis	Corynexochid trilobite.
Kootenia (?)[5]	Kootenia (?) sp.	Corynexochid trilobite.
Pseudagnostus[1][5]	P. josepha P. brighamensis P. bonnerensis	Agnostid trilobite.
Pagetia[5]	P. aspinosa P. rugosa P. claytonensis P. fossula	Agnostid trilobite.
Agnostoid[5]	Agnostoid sp. 1 Agnostoid sp. 2	Agnostid trilobite.
Bathyuriscus[3][5]	Bathyuriscus sp. B. terranovensis	Biceratopsid trilobite. Previously described as Wenkchemnia walcotti and W. sulcata.
Bolbolenellus[3]	B. brevispinus	Biceratopsid trilobite.
Olenellus[3][5]	Olenellus sp. O. puertoblancoensis (?)	Olenellid trilobite.
Wujiajiania[1]	W. sutherlandi	Olenellid trilobite.
Oryctocara[5]	Oryctocara sp.	Oryctocarid trilobite.
Oryctocarella[5]	Oryctocarella sp.	Oryctocarid trilobite.
Labiostria[1]	L. westropi	Aphelaspid trilobite.
Crassifimbra[3]	C. walcotti	Trilobite, family unknown.
Quasimodaspis[2]	O. brentsae	Tremaglaspidid artiopod.

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Lophotrochozoa

More information Genus, Species ...

Genus	Species	Notes	Images
Microcornus[4]	Microcornus sp.	Lophotrochozoan hyolith.
Parkula[6][4]	P. esmeraldina	Lophotrochozoan hyolith.
Haplophrentis[7]	H. carinatus	Lophotrochozoan hyolith.
Hyolithellus (?)[4]	Hyolithellus (?) sp.	Lophotrochozoan hyolith. May possibly be an annelid.[8]
Hyolithides[7]	???	Undetermined lophotrochozoan hyoliths, are either preserved as molds, or are too poorly preserved for identification.
Anabarella[6][4]	A. chelata	Helcionellid mollusc.
Pelagiella[4]	P. subangulata	Pelagiellid mollusc.
Costipelagiella[6][4]	C. nevadense	Pelagiellid mollusc.

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Ordovician

This section details all the fossils from the Ordovician unit at the top of the Emigrant Formation.