Marjum Formation

Marjum Formation
Stratigraphic range: Middle Cambrian
Notch Peak Sill intruding into the layers of white marble and grey argillite of the Marjum Formation
TypeGeological formation
OverliesWheeler Shale
ThicknessUp to 430 meters[1]
Lithology
Primarylimestone
Othershale, metasedimentary rocks
Location
Region Utah
Country USA
ExtentHouse Range
Type section
Named forMarjum Pass[2]
Named byCharles D. Walcott
Year defined1908[2]

The Marjum Formation is a Cambrian geological formation that overlies the Wheeler Shale in the House Range, Utah.[1][3] It is named after its type locality, Marjum Pass, and was defined in 1908.[2] The formation is known for its occasional preservation of soft-bodied tissue, and is slightly younger than the Burgess Shale,[4] falling in the Ptychagnostus praecurrens trilobite zone.[5]

Fossil content

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.

Ambulacrarians

Ambulacrarians reported from the Marjum Formation
Genus Species Presence Material Notes Images
Castericystis C. vali Numerous specimens.[6] A solutan.
Eldonia E. ludwigi Marjum Pass (Ptychagnostus punctuosus Zone).[7] SM X.50204.1 (part) & SM X.50204.2 (counterpart).[7] A cambroernid.
Marjumicystis M. mettae 7 specimens.[6] An eocrinoid.
Mastigograptus M. sp. A single specimen.[8] A mastigograptid graptolite.
Totiglobus T.? lloydi Locality 811.[9] 1 specimen (USNM 172047).[9] An edrioasteroid.

Arthropods

Arthropods reported from the Marjum Formation
Genus Species Presence Material Notes Images
Anomalocaris A. nathorsti Sponge Gully.[10] Partial body (USNM 374593).[10] Species moved to the genus Peytoia.
Asaphiscus A. wheeleri Bathyuriscus fimbriatus Subzone.[11] A ptychopariid trilobite.
Baltagnostus B. eurypyx All subzones of the Bolaspidella Zone.[11] Multiple specimens.[11] A diplagnostid trilobite.
Bathyuriscidella B. aff. B. amplicauda Bolaspidella contracta Subzone.[11] 3 pygidia.[11] A dolichometopid trilobite.
Bathyuriscus B. elegans Bolaspidella contracta Subzone.[11] Numerous specimens.[11] A dolichometopid trilobite.
B. fimbriatus Bathyuriscus fimbriatus & lower Bolaspidella contracta Subzone.[11] Numerous specimens.[11] A dolichometopid trilobite.
Bolaspidella B. contracta Bolaspidella contracta & lower Lepojyge calva Subzones.[11] A menomoniid trilobite.
B. housensis Bathyuriscus fimbriatus Subzone.[11] A menomoniid trilobite.
B. jarrardi Localities 347, 391, and 716 (mid-Bolaspidella Zone).[12] Multiple specimens.[12] A menomoniid trilobite.
Branchiocaris B. pretiosa Sponge Gully.[10][13] 3 specimens.[10] A hymenocarine.
Buccaspinea B. cooperi Kells Knolls locality.[14] An almost complete specimen (BPM 1108).[14] A hurdiid, originally reported as Hurdia sp.
Burlingia B. halgedahlae Localities 347 and 716 (mid-Bolaspidella Zone).[12] Multiple specimens.[12] A burlingiid trilobite.
Caryosyntrips C. camurus 'Red Wash' locality.[14] 2 isolated frontal appendages.[14] A panarthropod of uncertain classification.
Cotalagnostus C. laevus Bolaspidella contracta Subzone.[11] Over 50 specimens.[11] A diplagnostid trilobite.
C. sp. Bolaspidella contracta Subzone.[11] A pygidium. A diplagnostid trilobite.
Dicranocaris D. guntherorum Red Wash, Modocia Flats & Sponge Gully.[13] 4 specimens.[13] An arthropod of uncertain classification.
Dytikosicula D. desmatae West of Delta, House Range.[7] 1 specimen (SM X.50203).[7] A putative megacheiran.
Elrathia E. alapyge Bolaspidella contracta & Lejopyge calva Subzones.[11] Numerous specimens.[11] A ptychopariid trilobite.
E. marjumi Bathyuriscus fimbriatus & Bolaspidella contracta Subzones.[11] Numerous specimens.[11] A ptychopariid trilobite.
Emeraldella E.? sp. Red Wash.[10] Part & counterpart (KUMIP 204791).[10] An artiopod.
Hemirhodon H. amplipyge Bolaspidella contracta Subzone.[11] 14 incomplete specimens.[11] A dolichometopid trilobite.
Holteria H. problematica Marjum Pass (Lejopyge calva Subzone).[11] A pygidium.[11] A corynexochid trilobite.
Homagnostus H. incertus Bolaspidella contracta Subzone.[11] Multiple specimens.[11] An agnostid trilobite.
Hypagnostus H. parvifrons All subzones of the Bolaspidella Assemblage Zone.[11] Numerous specimens.[11] A diplagnostid trilobite.
Itagnostus I. interstrictus House Range.[15] A peronopsid trilobite originally reported as Peronopsis interstricta.
Leanchoilia L.? cf. protogonia Sponge Gully.[13] Part & counterpart of a complete specimen (UU 06011.01).[13] A megacheiran.
Lejopyge L. calva Marjum Pass (Lejopyge calva Subzone).[11] Numerous specimens.[11] A ptychagnostid trilobite.
Linguagnostus L. perplexus Bolaspidella contracta Subzone.[11] Over 20 specimens.[11] A diplagnostid trilobite.
Marjumia M. callas Bolaspidella contracta Subzone.[11] A marjumiid trilobite.
M. typa Bolaspidella contracta Subzone.[11] A marjumiid trilobite.
Modocia M. laevinucha Bathyuriscus fimbriatus & Bolaspidella contracta Subzones.[11] Many specimens.[11] A marjumiid trilobite.
M. nuchaspina Bolaspidella contracta Subzone.[11] A marjumiid trilobite.
M. typicalis 50 or more specimens.[11] A marjumiid trilobite.
Naraoia N. compacta Sponge Gully.[16] 4 specimens.[16] A naraoiid.
Neolenus N. inflatus East of Antelope Springs.[17] Multiple specimens & fragments.[17] A trilobite.
N. intermedius East of Antelope Springs.[17] A trilobite.
N. intermedius pugio East of Antelope Springs.[17] 4 specimens of a pygidium.[17] A trilobite.
N. superbus East of Antelope Springs.[17] Multiple specimens & fragments.[17] A trilobite.
Nettapezoura N. basilika Sponge Gully.[13] An arachnomorph.
Olenoides O. decorus Bolaspidella contracta Subzone.[11] 7 specimens.[11] A dorypygid trilobite.
O. inflatus Bolaspidella contracta Subzone.[11] A dorypygid trilobite.
O. marjumensis Bolaspidella contracta Subzone.[11] A dorypygid trilobite.
O. pugio Bolaspidella contracta Subzone.[11] Numerous specimens.[11] A dorypygid trilobite.
O. superbus Bolaspidella contracta Subzone.[11] 7 specimens.[11] A dorypygid trilobite.
Pahvantia P. hastata Precise localities unknown.[14] 3 specimens.[14] A hurdiid.
Peronopsis P. interstricta House Range.[15] Numerous specimens.[11] Reassigned to the genus Itagnostus.
P. segmenta House Range.[15] Multiple specimens.[11] A peronopsid trilobite.
Perspicaris P.? ellipsopelta Ptychagnostus punctuosus Zone.[18] Valves & carapaces.[18] A bivalved arthropod.
Peytoia P. nathorsti Sponge Gully.[10] Partial body (USNM 374593) & partial mouthpart (KUMIP 314095).[19] A hurdiid, formerly named Anomalocaris nathorsti.
Ptychagnostus P. akanthodes Bolaspidella contracta Subzone.[11] Numerous specimens.[11] A ptychagnostid trilobite.
P. atavus House Range.[15] A ptychagnostid trilobite.
P. hybridus Bolaspidella contracta Subzone.[11] About 10 specimens.[11] A ptychagnostid trilobite.
P. richmondensis Bathyuriscus fimbriatus Subzone.[11] Numerous specimens.[11] A ptychagnostid trilobite.
P. sp. Bolaspidella contracta Subzone.[11] At least 5 pygidia. A ptychagnostid trilobite.
Trymataspis T. depressa Bolaspidella contracta Subzone.[11] Over 30 specimens.[11] A lonchocephalid trilobite.
T. lomaleie Bolaspidella contracta Subzone.[11] 10 cranidia.[11] A lonchocephalid trilobite.
T. pristina Bolaspidella contracta Subzone.[11] Over 20 cranidia.[11] A lonchocephalid trilobite.
Tuzoia T. guntheri Ptychagnostus punctuosus Zone.[18] Multiple valves & carapaces.[18][20] A hymenocarine.
Utagnostus U. trispinulus Bolaspidella contracta & Lejopyge calva Subzones.[11] Multiple specimens.[11] An agnostid trilobite.
Utaspis U. marjumensis House Range & Wheeler Amphitheater.[11] A ptychopariid trilobite.
Zacanthoides Z. sp. Wheeler Amphitheater (Bolaspidella contracta Subzone).[11] A cranidium.[11] A zacanthoidid trilobite.

Chancelloriids

Chancelloriids reported from the Marjum Formation
Genus Species Presence Material Notes Images
Chancelloria C. sp. Bathyuriscus fimbriatus & Bolaspidella contracta Subzones.[11] About 20 spicules.[11] A chancelloriid.

Chordates

Chordates reported from the Marjum Formation
Genus Species Presence Material Notes Images
Megasiphon M. thylakos House Range.[21] One specimen (UMNH.IP.6079).[21] A tunicate.
Nuucichthys N. rhynchocephalus House range.[22] One specimen (UMNH.IP.6084)[22] A basal chordate related to Metaspriggina.
Skeemella S. clavula North of Red Wash (Ptychagnostus punctuosus Biozone).[23] 2 specimens (KUMIP 314102 & KUMIP 314103).[23] A vetulicolian.

Cnidarians

Moon, Caron & Moysiuk (2023) considered these fossils would be ctenophores instead.[24]

Cnidarians reported from the Marjum Formation
Genus Species Presence Material Notes Images
Coronatae? Indeterminate Sponge Gully.[25] 1 specimen (UU07021.05).[25] A scyphozoan jellyfish, may be referrable to the crown jellyfish family.
Cubozoa? Indeterminate Sponge Gully.[25] 2 specimens (UU07021.01 & UU07021.02).[25] Specimens possibly referrable to box jellyfish.
Narcomedusae? Indeterminate Sponge Gully.[25] 5 specimens (UU07021.03, UU07021.04, UU07021.06, UU07021.07 & UU07021.08).[25] A hydrozoan tentatively assigned to this family.
Semaeostomeae? Indeterminate Sponge Gully.[25] 2 specimens (UU07021.09 & UU07021.10).[25] A scyphozoan jellyfish tentatively assigned to this family.

Ctenophores

Ctenophores reported from the Marjum Formation
Genus Species Presence Material Notes Images
Ctenorhabdotus C. campanelliformis House Range (likely from the lower Ptychagnostus punctuosus Zone).[26] 1 specimen (UMNH.IP.6125).[26] A ctenophore.
Thalassostaphylos T. elegans House Range (lower Ptychagnostus punctuosus Zone).[26] 1 specimen (UMNH.IP.6086).[26] A ctenophore.

Lophotrochozoans

Lophotrochozoans reported from the Marjum Formation
Genus Species Presence Material Notes Images
Acrothele A. subsidua Bathyuriscus-Elrathina & Bolaspidella Zones.[11] A brachiopod.
Helcionella "H." arguta Bathyuriscus fimbriatus & Bolaspidella contracta Subzones.[11] More than 100 specimens.[11] A helcionellid.
Hyolithes H. sp. All subzones of the Bolaspidella Zone.[11] More than 100 specimens.[11] A hyolith.
Lingulella L. sp. Bathyuriscus fimbriatus & Bolaspidella contracta Subzones.[11] An obolid brachiopod.
Micromitra M. modesta Multiple specimens.[11] A paterinide brachiopod.
Nisusia N. sulcata 18 specimens.[27] A kutorginate brachiopod.
Pegmatreta P. bellatula Bathyuriscus fimbriatus & Bolaspidella contracta Subzones.[11] Numerous specimens.[11] A brachiopod.
P. ophirensis All subzones of the Bolaspidella Zone.[11] A brachiopod.
Pelagiella P. sp. Bolaspidella contracta Subzone.[11] More than 50 internal molds.[11] A pelagiellid.
Prototreta P. attenuata Bathyuriscus-Elrathina Zone & Bolaspidella Zone.[11] A brachiopod.
P. mimica Bolaspidella contracta Subzone.[11] A brachiopod.
Stenothecoides S. elongata Bathyuriscus fimbriatus Subzone.[11] Over 30 valves.[11] A stenothecoid.

Scalidophorans

Scalidophorans reported from the Marjum Formation
Genus Species Presence Material Notes Images
Arrakiscolex A. aasei Grey Marjum locality (Ptychagnostus punctuosus Zone).[28] Cuticle fragments.[28] A palaeoscolecid also known from the Upper Weeks Formation.
Ottoia O. prolifica Sponge Gully.[5] A complete individual (KUMIP 204770).[5] Referral of the specimen to this species is insecure, better classified as O.? sp.[28][29]
O.? sp. Sponge Gully.[28] A complete individual (KUMIP 204770).[28] A stem-priapulid, specimen formerly referred to Ottoia prolifica or Scathascolex minor.[28]
Scathascolex S. minor Sponge Gully.[5] A complete individual (KUMIP 204770).[5][30] Specimen reassigned to Ottoia? sp.[28]
Selkirkia S. willoughbyi Sponge Gully.[5] Tube with associated soft parts (KUMIP 204788).[5] A stem-priapulid.

Sponges

Sponges reported from the Marjum Formation
Genus Species Presence Material Notes Images
Choia C. carteri Sponge Gulch.[31] A demosponge.
C. hindei Red Cliffs Wash.[31] 2 specimens & 3 other fragments.[31] A demosponge.
C. utahensis Sponge Gulch.[31] Several specimens.[31] A demosponge.
Diagoniella D. cyathiformis Red Cliffs Wash & Kells Knolls Gulch.[31] Numerous specimens.[31] A reticulosan.
D. hindei Sponge Gulch.[31] Approximately 40 specimens.[31] A reticulosan.
D. magna Kells Knolls Gulch (Bathyuriscus fimbriatus zone).[32] A fragment (USNM 535922).[32] A reticulosan.
D. sp. Sponge Gulch.[31] 2 large fragments.[31] A reticulosan.
Hamptonia H. bowerbanki Red Cliffs Wash & Sponge Gulch.[31] Multiple specimens.[31] A demosponge.
Hazelia H. palmata Near Marjum Pass.[33] One specimen.[33] A demosponge.
Hintzespongia H. bilamina Kells Knolls Gulch (Bathyuriscus fimbriatus zone).[31][32] Multiple specimens.[31][32] A reticulosan.
Hexactinellida Indeterminate Miscellaneous spicules.[11] Indeterminate glass sponges, originally reported as Hyalospongiae (now a junior synonym).
Kiwetinokia Drum Mountains.[31] 4 large slabs.[31] A reticulosan.
Leptomitus L. metta Red Cliffs Wash locality.[31] 22 specimens.[31] A demosponge.
Polygoniella P. turrelli House Range[34] Around 200 specimens[34] A glass sponge
Protospongia P.? elongata Sponge Gulch.[31] 1 specimen.[31] A reticulosan.
Testiispongia T. venula Sponge Gulch.[31] Several specimens.[31] A glass sponge.
Valospongia V. gigantis Sponge Gulch.[31] A reticulosan.
V.? gigantus Kells Knolls Gulch (Bathyuriscus fimbriatus zone).[32] A fragment (USNM 535917).[32] A reticulosan.

See also

References

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