The Spence Shale is the middle

member Member may refer to: * Military jury, referred to as "Members" in military jargon * Element (mathematics), an object that belongs to a mathematical set * In object-oriented programming, a member of a class ** Field (computer science), entries in ...

of the Langston Formation in southeastern

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyomi ...

and northeastern

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...

. It is exposed in the

Bear River Range The Bear River Range (also known as the Bear River Mountains), is a mountain range located in northeastern Utah and southeastern Idaho in the western United States. __TOC__ Description The range forms the eastern boundary of the Cache Valley. O ...

, the

Wasatch Range The Wasatch Range ( ) or Wasatch Mountains is a mountain range in the western United States that runs about from the Utah-Idaho border south to central Utah. It is the western edge of the greater Rocky Mountains, and the eastern edge of the G ...

and the

Wellsville Mountains The Wellsville Mountains are located in northern Utah, United States and are often considered part of the Wasatch Mountains. Description The mountains separate Cache Valley from the Wasatch Front (Bear River Valley), as well as form a portion o ...

. It is known for its abundant Cambrian

trilobites Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the At ...

and the preservation of

Burgess Shale The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At old (middle Cambrian), it is one of the earliest fo ...

-type fossils. The type locality is Spence Gulch in southeastern

, near the town of Liberty. It was first described by

Charles Doolittle Walcott Charles Doolittle Walcott (March 31, 1850February 9, 1927) was an American paleontologist, administrator of the Smithsonian Institution from 1907 to 1927, and director of the United States Geological Survey. Wonderful Life (book) by Stephen Jay G ...

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 Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chitin, ...

Soft-bodied

*''

Anomalocaris ''Anomalocaris'' ("unlike other shrimp", or "abnormal shrimp") is an extinct genus of radiodont, an order of early-diverging stem-group arthropods. The first fossils of ''Anomalocaris'' were discovered in the ''Ogygopsis'' Shale of the Stephen F ...

'' *''

Canadaspis ''Canadaspis'' ("Shield of Canada") is an extinct genus of bivalved Cambrian arthropod, known from North America and China. They are thought to have been benthic feeders that moved mainly by walking and possibly used its biramous appendages to ...

'' *'' Caryosyntrips'' *'' Dioxycaris'' *''

Hurdia ''Hurdia'' is an extinct genus of hurdiid radiodont that lived 505 million years ago during the Cambrian Period. As a radiodont like ''Peytoia'' and ''Anomalocaris'', it is part of the ancestral lineage that led to euarthropods. Description ' ...

'' *''

Isoxys ''Isoxys'' (meaning "equal surfaces") is a genus of extinct bivalved Cambrian arthropod; the various species of which are thought to have been freely swimming predators. It had a pair of large spherical eyes (which are the most commonly preserve ...

'' *''

Leanchoilia ''Leanchoilia'' is an megacheiran arthropod known from Cambrian deposits of the Burgess Shale in Canada and the Chengjiang biota of China. It was about long and had long, whip-like feelers mounted on frontal arm-like appendages. Its internal o ...

'' *'' Meristosoma'' *''

Mollisonia ''Mollisonia'' is an extinct genus of Cambrian arthropod. Species are known from the Burgess Shale, Langston Formation, and Wheeler Shale of North America, as well as the Chengjiang Biota of China. Twenty-one specimens of ''Mollisonia'' are ...

'' *''

Sidneyia ''Sidneyia'' is an extinct arthropod known from fossils found from the Early Cambrian-age Maotianshan Shales to the Mid Cambrian Burgess Shale formation of British Columbia. 144 specimens of ''Sidneyia'' are known from the Greater Phyllopod be ...

'' *''

Tuzoia ''Tuzoia'' (from Mount Tuzo, a mountain in the Canadian Rockies) is an extinct genus of large bivalved arthropod known from Early to Middle Cambrian marine environments from what is now North America, Australia, China, Europe and Siberia. The larg ...

'' *'' Utahcaris'' *''

Waptia ''Waptia fieldensis'' is an extinct species of arthropod from the Middle Cambrian Burgess Shale ''Lagerstätte'' of Canada. It grew to a length of , and had a large bivalved carapace and a segmented body terminating into a pair of tail flaps. I ...

'' *''

Yohoia ''Yohoia'' is an extinct genus of megacheiran arthropod from the Cambrian period that has been found as fossils in the Burgess Shale formation of British Columbia, Canada. It has been placed among the arachnomorpha, a group of arthropods that in ...

Agnostida

*''

Pentagnostus ''Pentagnostus'' is a genus of trilobites restricted to the Middle Cambrian. Its remains have been found in Siberia, Australia, North America, Scandinavia, and Kazakhstan. Taxonomy The probable ancestor of ''Pentagnostus'' is Archaeagnostus. T ...

'' *''

Ptychagnostus ''Ptychagnostus'' is a member of the agnostida that lived during the Cambrian period. Ptychagnostidae generally do not exceed one centimetre in length. Their remains are rarely found in empty tubes of the polychaete worm '' Selkirkia''. The gen ...

Trilobita Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the At ...

*'' Alokistocare'' *'' Alokistocarella'' *'' Amecephalus'' *'' Athabaskia'' *'' Bathyuriscus'' *'' Bythicheilus'' *'' Chancia'' *''

Ehmaniella ''Ehmaniella'' is a genus of trilobite known from the Middle Cambrian Burgess Shale. 392 specimens of ''Ehmaniella'' are known from the Greater Phyllopod bed, where they comprise 0.74% of the community. Ehmaniella's major characteristics are a ...

'' *'' Glossopleura'' *'' Kochina'' *''

Kootenia ''Kootenia'' is a genus of trilobites of the family Dorypygidae. 118 specimens of ''Kootenia'' are known from the Greater Phyllopod bed, where they comprise 0.22% of the community. Its major characteristics are that of the closely related ''Olen ...

'' *''

Ogygopsis ''Ogygopsis'' is a genus of trilobite from the Cambrian of Antarctica and North America, specifically the Burgess Shale. It is the most common fossil in the Mt. Stephen fossil beds there, but rare in other Cambrian faunas. Its major characteristi ...

'' *'' Olenoides'' *'' Oryctocara'' *'' Oryctocephalites'' *'' Oryctocephalus'' *''

Pagetia ''Pagetia'' Walcott, 1916. is a small genus of trilobite, assigned to the Eodiscinid family Pagetiidae and which had global distribution during the Middle Cambrian. The genus contains 55 currently recognized species, each with limited spatial ...

'' *'' Piochaspis'' *'' Polypleuraspis'' *'' Ptychoparella'' *'' Solenopleura'' *'' Syspacephalus'' *''

Thoracocare ''Thoracocare'' is a minute to very small (1.7 – 3.6 mm long) trilobite, that lived during part of the Middle Cambrian in what are today the states of Idaho, Nevada and Utah. It is the only trilobite known with just two thorax segments ou ...

'' *'' Utia'' *''

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

Brachiopoda

*'' Acrothele'' *'' Dictyonina'' *'' Diraphora'' *'' Lingulella'' *'' Micromitra''? *'' Wimanella''

Mollusca

*''

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, spiral ...

'' *'' Scenella'' *''

Wiwaxia ''Wiwaxia'' is a genus of soft-bodied animals that were covered in carbonaceous scales and spines that protected it from predators. ''Wiwaxia'' fossils – mainly isolated scales, but sometimes complete, articulated fossils – are known from ear ...

Lophotrochozoa Lophotrochozoa (, "crest/wheel animals") is a clade of protostome animals within the Spiralia. The taxon was established as a monophyletic group based on molecular evidence. The clade includes animals like annelids, molluscs, bryozoans, brachi ...

*'' Haplophrentis'' *'' Hyolithellus'' *''

Hyolithes Hyoliths are animals with small conical shells, known as fossils from the Palaeozoic era. They are at least considered as lophotrochozoan, and possibly being lophophorates, a group which includes the brachiopods, while others consider them as be ...

Echinodermata An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the s ...

*'' Ctenocystis'' *''

Gogia ''Gogia'' is a genus of primitive eocrinoid blastozoan from the early to middle Cambrian. ''G. ojenai'' dates to the late Early Cambrian; other species come from various Middle Cambrian strata throughout North America, but the genus has yet to ...

'' *''

Lyracystis ''Lyracystis radiata'' is an extinct genus of Cambrian eocrinoid echinoderm, fossils of which are known from the Burgess Shale of British Columbia, Canada. It is related to ''Gogia ''Gogia'' is a genus of primitive eocrinoid blastozoan from t ...

'' *'' Ponticulocarpus'' *'' Totiglobus''

Hemichordata

*''

Margaretia ''Margaretia'' is a frondose organism known from the middle Cambrian Burgess shale and the Kinzers Formation of Pennsylvania. Its fronds reached about 10 cm in length and are peppered with a range of length-parallel oval holes. It was or ...

'' *'' Sphenoecium''

Priapulida Priapulida (priapulid worms, from Gr. πριάπος, ''priāpos'' 'Priapus' + Lat. ''-ul-'', diminutive), sometimes referred to as penis worms, is a phylum of unsegmented marine worms. The name of the phylum relates to the Greek god of fertility ...

*''

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 th ...

'' *'' Selkirkia'' *'' Wronascolex''?

Lobopodia The lobopodians, members of the informal group Lobopodia (from the Greek, meaning "blunt feet"), or the formally erected phylum Lobopoda Cavalier-Smith (1998), are panarthropods with stubby legs called lobopods, a term which may also be used as ...

*'' Acinocricus'' *''

Hallucigenia ''Hallucigenia'' is a genus of Cambrian animal resembling worms, known from articulated fossils in Burgess Shale-type deposits in Canada and China, and from isolated spines around the world. The generic name reflects the type species' unusual ...

Porifera

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

Problematica

*''

Banffia ''Banffia'' is a genus of animals described from Middle Cambrian fossils. The genus commemorates Banff, Alberta, near where the first fossil specimens were discovered. Its placement in higher taxa is controversial. It is considered to be a memb ...

'' *'' Eldonia'' *'' Siphusauctum''

Algae

*''

Marpolia ''Marpolia'' has been interpreted as a cyanobacterium, but also resembles the modern cladophoran green algae. It is known from the Middle Cambrian Burgess shale and Early Cambrian deposits from the Czech Republic. It comprises a dense mass of e ...

Cyanobacteria

*'' Morania''

Trace Fossils 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 fossils contrast with body fossils ...

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

Coprolite A coprolite (also known as a coprolith) is fossilized feces. Coprolites are classified as trace fossils as opposed to body fossils, as they give evidence for the animal's behaviour (in this case, diet) rather than morphology. The name is de ...

*''

Cruziana ''Cruziana'' is a trace fossil consisting of elongate, bilobed, approximately bilaterally symmetrical burrows, usually preserved along bedding planes, with a sculpture of repeated striations that are mostly oblique to the long dimension. It is fo ...

'' *'' Dimorphichnus'' *''

Diplichnites ''Diplichnites'' are arthropod trackways with two parallel rows of blunt to elongate, closely spaced tracks oriented approximately perpendicularly to the mid-line of the trackway. The term is more often used for the ichnofossils of this descripti ...

'' *'' Gordia'' *'' Gyrophyllites'' *'' Halopoa'' *'' Lockeia'' *'' Monomorphichnus'' *'' Nereites'' *''

Phycodes ''Phycodes'' is a genus of moths in the family Brachodidae Brachodidae is a family of day-flying moths, commonly known as little bear moths, which contains about 135 species distributed around much of the world (Edwards et al. 1999). The rela ...

'' *'' Phycosiphon'' *'' Planolites'' *'' Protovirgularia'' *'' Rusophycus'' *'' Sagittichnus'' *''

Scolicia ''Scolicia'' de Quartrefages, 1849 is a parataxon of ichnofossils present in sedimentary rock Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, follow ...

'' *'' Taenidium'' *''

Teichichnus ''Teichichnus'' is an ichnogenus with a distinctive form produced by the stacking of thin 'tongues' of sediment, atop one another. They are believed to be fodinichnia, with the organism adopting the habit of retracing the same route through var ...

'' *'' Tomaculum'' *'' Treptichnus'' *'' 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

Stratigraphy

Fauna

Arthropoda Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chitin, ...

Trilobita Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the At ...

Lophotrochozoa Lophotrochozoa (, "crest/wheel animals") is a clade of protostome animals within the Spiralia. The taxon was established as a monophyletic group based on molecular evidence. The clade includes animals like annelids, molluscs, bryozoans, brachi ...

Echinodermata An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the s ...

Priapulida Priapulida (priapulid worms, from Gr. πριάπος, ''priāpos'' 'Priapus' + Lat. ''-ul-'', diminutive), sometimes referred to as penis worms, is a phylum of unsegmented marine worms. The name of the phylum relates to the Greek god of fertility ...

Lobopodia The lobopodians, members of the informal group Lobopodia (from the Greek, meaning "blunt feet"), or the formally erected phylum Lobopoda Cavalier-Smith (1998), are panarthropods with stubby legs called lobopods, a term which may also be used as ...

Trace Fossils 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 fossils contrast with body fossils ...

See also

References