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
Type	Geological formation
Overlies	Wheeler Shale
Thickness	Up to 430 meters [1]
Lithology
Primary	limestone
Other	shale, metasedimentary rocks
Location
Region	Utah
Country	United States
Extent	House Range
Type section
Named for	Marjum Pass [2]
Named by	Charles D. Walcott
Year defined	1908 [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	Bolaspidellacontracta & 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]	Originally considered as a scyphozoan jellyfish, may be referrable to the crown jellyfish family, later reclassified to stem-ctenophore Calathites macrocalyx . [26]
Cubozoa?	Indeterminate	Sponge Gully. [25]	2 specimens (UU07021.01 & UU07021.02). [25]	Specimens possibly referrable to box jellyfish. Later reclassified to stem-ctenophore Calathites macrocalyx and Theiokylinxia cartwrightae . [26]
Narcomedusae?	Indeterminate	Sponge Gully. [25]	5 specimens (UU07021.03, UU07021.04, UU07021.06, UU07021.07 & UU07021.08). [25]	Originally considered as a hydrozoan tentatively assigned to this family. Later reclassified to stem-ctenophore Theiokylinxia cartwrightae and indeterminate dinomischid for figured specimens. [26]
Semaeostomeae?	Indeterminate	Sponge Gully. [25]	2 specimens (UU07021.09 & UU07021.10). [25]	Originally considered as a scyphozoan jellyfish tentatively assigned to this family. Later reclassified to indeterminate stem-ctenophore dinomischid. [26]

Ctenophores

Ctenophores reported from the Marjum Formation
Genus	Species	Presence	Material	Notes	Images
Calathites	C. macrocalyx	House Range		A stem-group ctenophore within the family Dinomischidae. [26]
Ctenorhabdotus	C. campanelliformis	House Range (likely from the lower Ptychagnostus punctuosus Zone). [27]	1 specimen (UMNH.IP.6125). [27]	A ctenophore.
Dinomischidae	Indeterminate	House Range
Dinomischus	D. nudus	House Range		A stem-group ctenophore within the family Dinomischidae. [26]
	D. sp. A	House Range
Thalassostaphylos	T. elegans	House Range (lower Ptychagnostus punctuosus Zone). [27]	1 specimen (UMNH.IP.6086). [27]	A ctenophore.
Theiokylixia	T. cartwrightae	House Range		A stem-group ctenophore within the family Dinomischidae. [26]

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. [28]	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). [29]	Cuticle fragments. [29]	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. [29] [30]
	O.? sp.	Sponge Gully. [29]	A complete individual (KUMIP 204770). [29]	A stem-priapulid, specimen formerly referred to Ottoia prolifica or Scathascolex minor. [29]
Scathascolex	S. minor	Sponge Gully. [5]	A complete individual (KUMIP 204770). [5] [31]	Specimen reassigned to Ottoia? sp. [29]
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. [32]		A demosponge.
	C. hindei	Red Cliffs Wash. [32]	2 specimens & 3 other fragments. [32]	A demosponge.
	C. utahensis	Sponge Gulch. [32]	Several specimens. [32]	A demosponge.
Diagoniella	D. cyathiformis	Red Cliffs Wash & Kells Knolls Gulch. [32]	Numerous specimens. [32]	A reticulosan.
	D. hindei	Sponge Gulch. [32]	Approximately 40 specimens. [32]	A reticulosan.
	D. magna	Kells Knolls Gulch (Bathyuriscus fimbriatus zone). [33]	A fragment (USNM 535922). [33]	A reticulosan.
	D. sp.	Sponge Gulch. [32]	2 large fragments. [32]	A reticulosan.
Hamptonia	H. bowerbanki	Red Cliffs Wash & Sponge Gulch. [32]	Multiple specimens. [32]	A demosponge.
Hazelia	H. palmata	Near Marjum Pass. [34]	One specimen. [34]	A demosponge.
Hintzespongia	H. bilamina	Kells Knolls Gulch (Bathyuriscus fimbriatus zone). [32] [33]	Multiple specimens. [32] [33]	A reticulosan.
Hexactinellida	Indeterminate		Miscellaneous spicules. [11]	Indeterminate glass sponges, originally reported as Hyalospongiae (now a junior synonym).
Kiwetinokia		Drum Mountains. [32]	4 large slabs. [32]	A reticulosan.
Leptomitus	L. metta	Red Cliffs Wash locality. [32]	22 specimens. [32]	A demosponge.
Polygoniella	P. turrelli	House Range [35]	Around 200 specimens [35]	A glass sponge
Protospongia	P.? elongata	Sponge Gulch. [32]	1 specimen. [32]	A reticulosan.
Testiispongia	T. venula	Sponge Gulch. [32]	Several specimens. [32]	A glass sponge.
Valospongia	V. gigantis	Sponge Gulch. [32]		A reticulosan.
	V.? gigantus	Kells Knolls Gulch (Bathyuriscus fimbriatus zone). [33]	A fragment (USNM 535917). [33]	A reticulosan.

See also

• Earth sciences portal
• Utah portal
• Paleontology portal

• List of fossiliferous stratigraphic units in Utah
• Paleontology in Utah

References

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