The Spence Shale is the middle member of the

Langston Formation The Langston Formation is a geologic formation in Idaho and Utah. It preserves fossils dating back to the Cambrian period. The formation is composed of bluish-gray limestone, weathering to a buff color, often with rounded edges.Mansfield, Geor ...

in southeastern Idaho and northeastern Utah. It is exposed in the Bear River Range, the Wasatch Range and the Wellsville Mountains. It is known for its abundant

Cambrian The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million ...

trilobites and the preservation of Burgess Shale-type fossils. The type locality is Spence Gulch in southeastern Idaho, near the town of Liberty. It was first described by Charles Doolittle Walcott in 1908.

Stratigraphy

The Spence Shale spans the '' Albertella'' and '' Glossopleura'' biozones.

Fauna

Generic list of the fauna of the Spence Shale:Hammersburg, S.R., Hasiotis, S.T., Robison, R.R. 2018. Ichnotaxonomy of the Cambrian Spence Shale Member of the Langston Formation, Wellsville Mountains, Northern Utah, USA. Paleontological Contributions, 20, 1–66.

Arthropoda

Soft-bodied

*'' Anomalocaris'' *'' Canadaspis'' *''

Caryosyntrips ''Caryosyntrips'' ("nutcracker") is an extinct genus of radiodont which known from Canada, United States and Spain during the middle Cambrian. ''Caryosyntrips'' is known only from its 14-segmented frontal appendages, which resemble nutcrackers, r ...

'' *'' Dioxycaris'' *'' Hurdia'' *'' Isoxys'' *'' Leanchoilia'' *'' Meristosoma'' *'' Mollisonia'' *'' Sidneyia'' *'' Tuzoia'' *'' Utahcaris'' *'' Waptia'' *'' Yohoia''

Agnostida Agnostida is an order of arthropod which have classically been seen as a group of highly modified trilobites, though some recent research has doubted this placement. Regardless, they appear to be close relatives as part of the Artiopoda. They a ...

*'' Pentagnostus'' *'' Ptychagnostus''

Trilobita

*'' Alokistocare'' *'' Alokistocarella'' *'' Amecephalus'' *'' Athabaskia'' *''

Bathyuriscus ''Bathyuriscus'' is an extinct genus of Cambrian trilobite. It was a nektobenthic predatory carnivore. The genus Bathyuriscus is endemic to the shallow seas that surrounded Laurentia. Its major characteristics are a large forward-reaching glabella ...

'' *'' Bythicheilus'' *''

Chancia Chancia () is a commune in the Jura department Department may refer to: * Departmentalization, division of a larger organization into parts with specific responsibility Government and military *Department (administrative division), a geogr ...

'' *'' Ehmaniella'' *'' Glossopleura'' *'' Kochina'' *'' Kootenia'' *'' Ogygopsis'' *''

Olenoides ''Olenoides'' was a trilobite from the Cambrian period. Its fossils are found well-preserved in the Burgess Shale in Canada. It grew up to 10 cm (3.9 in) long. Etymology ''Olenoides'' – from ''Olenus'', in Greek mythology a man who, alon ...

'' *'' Oryctocara'' *'' Oryctocephalites'' *''

Oryctocephalus ''Oryctocephalus'' is a genus of trilobite known from the Middle Cambrian Burgess Shale. 24 specimens of ''Oryctocephalus'' are known from the Greater Phyllopod bed, where they comprise 0.42% of the community. This small- to medium-sized trilobit ...

'' *'' Pagetia'' *'' Piochaspis'' *'' Polypleuraspis'' *'' Ptychoparella'' *'' Solenopleura'' *'' Syspacephalus'' *'' Thoracocare'' *'' Utia'' *''

Zacanthoides ''Zacanthoides'' is an extinct Cambrian genus of corynexochid trilobite. It was a nektobenthic predatory carnivore. Its remains have been found in Canada ( British Columbia, especially in the Burgess Shale, and Newfoundland), Greenland, Me ...

Brachiopoda

*'' Acrothele'' *'' Dictyonina'' *''

Diraphora ''Diraphora'' is an extinct genus of brachiopod that lived in the Cambrian. Its remains have been found in Australia and North America. 664 specimens of ''Diraphora'' are known from the Greater Phyllopod bed, where they comprise 1.26% of the ...

'' *''

Lingulella ''Lingulella'' is a genus of phosphatic-shelled brachiopod. It is known from the Middle Cambrian Burgess Shale (Canada) to the Upper Ordovician Bromide Formation (United States) in North America.Amsden, T.W. Catalogue of Fossils from the Middle a ...

'' *''

Micromitra ''Micromitra'' is a genus of brachiopods known from the Middle Cambrian Burgess Shale. 160 specimens of ''Micromitra'' are known from the Greater Phyllopod bed The Phyllopod bed, designated by USNM locality number 35k, is the most famous fossil ...

''? *'' Wimanella''

Mollusca Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

*''

Latouchella ''Latouchella'' is an extinct genus of marine invertebrate animal, that is considered to be a mollusk and which may be a sea snail, a gastropod. It is a helcionellid from the Tommotian epoch of what is now Siberia. Its tightly coiled, spira ...

'' *''

Scenella ''Scenella'' is an extinct genus of fossil invertebrate animal which is generally considered to be a mollusc; at various times it has been suggested that this genus belongs with the gastropods, the monoplacophorans, or the helcionellids, althou ...

'' *'' Wiwaxia''

Lophotrochozoa

*'' Haplophrentis'' *''

Hyolithellus ''Hyolithellus'' is a conical tubular fossil from the Cambrian, originally considered a hyolith but since reinterpreted tentatively as an annelid The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are ...

'' *'' Hyolithes''

Echinodermata

*'' Ctenocystis'' *'' Gogia'' *'' Lyracystis'' *'' Ponticulocarpus'' *'' Totiglobus''

Hemichordata

*'' Margaretia'' *'' Sphenoecium''

Priapulida

*''

Ottoia ''Ottoia'' is a stem-group archaeopriapulid worm known from Cambrian fossils. Although priapulid-like worms from various Cambrian deposits are often referred to ''Ottoia'' on spurious grounds, the only clear ''Ottoia'' macrofossils come from the ...

'' *''

Selkirkia ''Selkirkia'' is a genus of predatory, tubicolous priapulid worms known from the Middle Cambrian Burgess Shale, Ogygopsis Shale and Puncoviscana Formation. 142 specimens of ''Selkirkia'' are known from the Greater Phyllopod bed, where they compr ...

'' *'' Wronascolex''?

Lobopodia

*''

Acinocricus ''Acinocricus'' is a genus of extinct worm belonging to the group Lobopodia and known from the middle Cambrian Spence Shale of Utah, United States. As a monotypic genus, it has one species ''Acinocricus stichus''. The only lobopodian discovered f ...

'' *'' Hallucigenia''

Porifera Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through th ...

*'' Brooksella''? *'' Protospongia'' *''

Vauxia ''Vauxia'' is an extinct genus of demosponge that had a distinctive branching mode of growth. Each branch consisted of a network of strands. ''Vauxia'' also had a skeleton of spongin (flexible organic material) common to modern day sponges. Much ...

Problematica

*'' Banffia'' *''

Eldonia ''Eldonia'' is an extinct soft-bodied cambroernid animal of unknown affinity, best known from the Fossil Ridge outcrops of the Burgess Shale, particularly in the 'Great ''Eldonia'' layer' in the Walcott Quarry. In addition to the 550 collected b ...

'' *''

Siphusauctum ''Siphusauctum'' is an extinct genus of filter-feeding animals that lived during the Middle Cambrian about 510 million years ago. Attached to the substrate by a holdfast, it had a tulip-shaped body, called the calyx, into which it actively pumpe ...

Algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

*'' Marpolia''

Cyanobacteria Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blu ...

*''

Morania ''Morania'' is a genus of cyanobacterium preserved as carbonaceous films in the Middle Cambrian Burgess Shale. it is present throughout the shale; 2580 specimens of ''Morania'' are known from the Greater Phyllopod bed, where they comprise 4.90% ...

Trace Fossils

*'' Archaeonassa'' *'' Arenicolites'' *'' Aulichnites'' *'' Bergaueria'' *'' Chloephycus'' *''

Conichnus ''Conichnus'' is an ichnogenus of trace fossil. See also * Ichnology References External links Chuck D. Howell's Ichnogenera Photos* Burrow fossils {{trace-fossil-stub ...

'' * Coprolite *'' Cruziana'' *'' Dimorphichnus'' *'' Diplichnites'' *''

Gordia ''Gordia'' is an ichnofossil A trace fossil, also known as an ichnofossil (; from el, ἴχνος ''ikhnos'' "trace, track"), is a fossil record of biological activity but not the preserved remains of the plant or animal itself. Trace fos ...

'' *'' Gyrophyllites'' *'' Halopoa'' *'' Lockeia'' *''

Monomorphichnus ''Monomorphichnus'' is an arthropod trace fossil known from the base of the Cambrian period onwards, before the first trilobite fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living th ...

'' *''

Nereites ''Nereites'' is a genus of trace fossil. Modern tracemakers of incipient ''Nereites'' include worm-like organisms,Seilacher, A., 2007. Trace Fossil Analysis. Springer, Berlin, Heidelberg (226 pp.) horseshoe crabsMartin, A.J., Rindsberg, A.K., 20 ...

'' *'' Phycodes'' *''

Phycosiphon ''Phycosiphon'' is an ichnogenus of trace fossil. The first recorded fossil was found in Scunthorpe, United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a countr ...

'' *''

Planolites ''Planolites'' is an ichnogenus found throughout the Ediacaran and the Phanerozoic that is made during the feeding process of worm-like animals. The traces are generally small, , unlined, and rarely branched, with fill that differs from the hos ...

'' *'' Protovirgularia'' *'' Rusophycus'' *'' Sagittichnus'' *'' Scolicia'' *''

Taenidium Taenidia (singular: taenidium) are circumferential thickenings of the cuticle inside a trachea or tracheole in an insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group with ...

'' *'' Teichichnus'' *'' Tomaculum'' *''

Treptichnus ''Treptichnus'' (formerly named ''Phycodes'', ''Manykodes'' by J. Dzik, and also known as ''Trichophycus''See e.gfossiilid.info: paleodiversity in Baltoscandia: Trichophycus pedum/ref>) is the preserved burrow of an animal. As such, it is regar ...

'' *'' Trichophycus''

References

* Shale formations of the United States Cambrian Idaho Cambrian geology of Utah Cambrian System of North America Cambrian southern paleotropical deposits {{Cambrian-stub