Trilobites of the Spence Shale Formation






Achylsopsis sp.

Achlysopsis n. sp.
Alokistocarella brighamensis Resser 1939b

Amecephalus laticaudum (Resser 1939a)

Amecephalus idahoense (Resser 1939a)

Amecephalus sp. 1

Amecephalus n. spp.

Athabaskia bithus (Walcott 1916)

Athabaskia howelli (Walcott, 1886)

Athabaskia wasatchensis (Resser 1939b)

Athabaskia  n. sp.

Bathyuriscus brighamensis Resser 1939a
Bathyuriscus wasatchensis (Resser 1939b)
Bythicheilus typicum Resser, 1939a

Caborcella n. sp.
Chancia cf. ebdome Walcott 1924

Dorypyge n. sp.

Glossopleura bion (Walcott 1916)

Glossopleura gigantea Resser 1939a

Glossopleura prona? Resser 1939b

Glossopleura sp.

Glossopleura n. sp.

Kootenia germana Resser 1939b
Kootenia mendosa Resser 1939b

Kootenia spencei Resser 1939a (not spenci)

Kootenia n. sp.

Ogygopsis typicalis (Resser 1939b)
Olenoides n. sp.
Onchocephalus? n. sp.
Oryctocara geikiei Walcott 1908
Oryctocephalites walcotti (Resser 1938)
Pagetia clytia Walcott 1916
Pagetia cf. fossula Resser 1938
Pagetia n. sp.
Peronopsis bonnerensis (Resser 1938)
Peronopsis brighamensis (Resser 1939a)
Peronopsis praecurrens (Westergard 1936)
Polypleuraspis cf. insignis Rasetti 1951
Prohedinia? n. sp.
Syspacephalus spencei (Resser 1939a)
Thoracocare minuta (Resser 1939a)
Utia curio Walcott 1924
Zacanthoides n. sp.

Zacanthoides grabaui Pack 1906

Zacanthoides idahoensis

Zacanthoides sp. (which species is this?)





Amecephalus idahoense (Resser 1939a)





Kochina vestina



Spence Shale Member, Langston Dolomite (455m)

-compiled by Dr. L. McCollum (site currently under investigation)


1.        Achlysopsis n. sp.
2.        Alokistocarella brighamensis Resser 1939b
3.        Amecephalus idahoense (Resser 1939a)
4.        Amecephalus laticaudum (Resser 1939a)
5.        Amecephalus n. spp.
6.        Athabaskia bithus (Walcott 1916)
7.        Athabaskia wasatchensis (Resser 1939b)
8.        Bathyuriscus brighamensis Resser 1939a
9.        Bathyuriscus wasatchensis (Resser 1939b)
10.       Bythicheilus typicum Resser 1939a   (TYPE)
11.       Caborcella n. sp.
12.       Chancia cf. ebdome Walcott 1924
13.       Dorypyge n. sp.
14.       Glossopleura bion (Walcott 1916)
15.       Glossopleura gigantea Resser 1939a
16.       Glossopleura n. sp.
17.       Glossopleura prona? Resser 1939b
18.       Kootenia germana Resser 1939b
19.       Kootenia n. sp.
20.       Kootenia mendosa Resser 1939b
21.       Kootenia spencei Resser 1939a
22.       Ogygopsis typicalis (Resser 1939b)
23.       Olenoides n. sp.
24.       Onchocephalus? n. sp.
25.       Oryctocara geikiei Walcott 1908
26.       Oryctocephalites walcotti (Resser 1938)
27.       Pagetia clytia Walcott 1916
28.       Pagetia cf. fossula Resser 1938
29.       Pagetia n. sp.
30.       Peronopsis bonnerensis (Resser 1938)
31.       Peronopsis brighamensis (Resser 1939a)
32.       Peronopsis praecurrens (Westergard 1936)
33.       Polypleuraspis cf. insignis Rasetti 1951
34.       Prohedinia? n. sp.
35.       Syspacephalus spencei (Resser 1939a)
36.       Thoracocare minuta (Resser 1939a)
37.       Utia curio Walcott 1924
38.       Zacanthoides n. sp.
39.       Zacanthoides grabaui Pack 1906



Two Mile Canyon Section (from Fritz, in Oriel & Armstrong, 1971, USGS Prof. Paper 394)

-compiled by Dr. L. McCollum (site currently under investigation)


1.        Alokistocarella occidens Resser 1939b
2.        Ogygopsis typicalis (Resser 1939b)
3.        Pachyaspis longa? Fritz 1968
4.        Pachyaspis typicalis Resser 1939b   (TYPE)
5.        Macannaia maladensis (Resser 1939b) 
6.        Pagetia rugosa Rasetti 1966
7.        Peronopsis bonnerensis (Resser 1938)




(or? Langston Formation, Spence Shale Member.)
The following trilobites are reported there (both Idaho & Utah)

-data compiled by J. Cook and Linda McCollum


Achylsopsis sp.

Achlysopsis n. sp.
Alokistocarella brighamensis Resser 1939b

A. spencei Resser 1939a
Amecephalus idahoensis
(Resser 1939a)

A. laticaudum (Resser 1939a)

A. punctatum (Resser, 1939a)

A. septum (Resser, 1939a)

A. spencense (Resser, 1939a)

Athabaskia anax (Walcott, 1916)

Athabaskia bithus (Walcott 1916)

A. wasatchensis (Resser 1939b)
Bathyuriscus atossa
Walcott, 1916

B. brighamensis Resser 1939a

B. wasatchensis (Resser 1939b)
Bythicheilus alveatum Resser 1939a

B. typicum Resser 1939a
Chancia angusta Resser 1939a

C. ebdome Walcott 1924

C. evax Walcott 1925
Clavaspidella anax = Athabaskia
anax (Walcott, 1916)

C. bithus = Athabaskia bithus (Walcott, 1916)

Dorypyge n. sp.

?Ehmaniella [= Clappaspis] coriacea (Resser 1939a)

?E. dotis (Resser 1939a)

?E. idahoensis (Resser 1939a)

?E. lanata (Resser 1939a)

?E. spencei (Resser 1939a)

Elrathia rara Resser 1939a

E. spencei Resser 1939a
Glossopleura bion (Walcott 1916)

G. gigantea Resser 1939a

G. similaris Resser 1939a

G. utahensis Resser 1939a

G. sp. [7 segments]
Kochina sp.
Kootenia gracilis Resser 1939a

K. idahoensis Resser 1939a

K. mathewsi Resser 1939a

K. spencei Resser 1939a

Ogygopsis typicalis (Resser 1939b)

Olenoides brighamensis Resser 1939a

O. evansi Resser 1939a
Oryctocara geikiei
Walcott 1908
Oryctocephalites typicalis

O. walcotti  (Resser 1938)
Pachyaspis typicalis
Resser 1939b
Pagetia clytia
Walcott 1916

Peronopsis bonnerensis (Resser 1938) [= Agnostus bonnerensis]
Peronopsis brighamensis (Resser 1939a)
Poliella anteros
(Walcott, 1916)

Poliella caranus Poliella anteros (Walcott, 1916)

Poliella germana (Resser 1939b)

Poliella cf. germana (Resser 1939b)

Ptychoparella [=Elrathina] offula (Resser 1939a)
Solenopleura sp.
Spencia plena Resser 1939a

Spencia typicalis Resser 1939a
Thoracocare minuta
(Resser 1939a)
Utia curio
Walcott 1924
Zacanthoides abbreviatus
Resser 1939a

Z. adjunctus Resser 1939a

Z. grabaui Pack 1906

Z. gradatus Resser 1939a

Z. holopygus Resser 1939a
Z. idahoensis
Walcott, 1908

Z. serratus Resser 1939a



Note: Previously reported Bolaspidella sp. and Coosella sp. should not occur here, as this formation is too much too old to have both these genera in it. Asaphiscus wheeleri also does not occur in the Spence Shale. The species of Dorypyge in the Spence is not D. swasii, so it is listed as D. n. species. Olenoides wahsatchensis (Hall & Whitfield 1877) appears to be from the Ute Formation, not the Spence Shale. Achylsopsis typicum is an unconfirmed name (so far by us), reported from the Spence. If anyone has any information on this species, please let us know.

     Resser (1939a,b) included Athabaskia Raymond 1928 in Clavaspidella Poulsen 1927, but Rasetti (1951, p. 156), Lochman (1952, p. 128) and Palmer (1954, p. 66) have all considered Athabaskia to be distinct from Clavaspidella (which is a Greenland genus). Therefore all of the "Clavaspidella" Poulsen 1927 species found in the Spence Shale were reassigned to Athabaskia Raymond 1928.

     The FAD of Ehmaniella marks the upper boundary of the Glossopleura Biozone, therefore these genera don't overlap. Ehmaniella does occur in the Ute Formation, but not the Spence Shale. Until these species are reassigned to other genera, we call them ?Ehmaniella. Ehmaniella quadrans (Hall & Whitfield 1877) is the type species and occurs only in the overlying Ute Formation.

    Albertella ? sp. reported from the Spence is not likely as this genus occurs only below the Spence (in the Naomi Peak Limestone Member). Alokistocare is restricted to a younger biozone, so all species from the Spence should now be Amecephalus. Anomocare sp. is most likely misidentified, as there is no record of this genus occurring in the Spence Shale - it is from the Paradoxides Biozone of Sweden.



    If you know of any other species from this formation, or have additional specimens or information, please contact Dr. Linda McCollum at: Eastern Washington University 130 Science Building Cheney, WA99004-2439 USA,





Gunther, Lloyd F. & Val G. (1981)  Some Middle Cambrian Fossils of Utah. Brigham Young University Geology Studies, Volume 28, Part 1


Fritz, in Oriel & Armstrong, 1971. USGS Prof. Paper 394


Hintze, Lehi F. (1973) Geologic History of Utah. Brigham Young University, Geology Studies 20(3):15-164


Liddell, W David; Wright, Scott H.; Brett, Carlton E.; 1997. Sequence stratigraphy and paleoecology of the Middle Cambrian Spence Shale in northern Utah and southern Idaho. Brigham Young University, Geology Studies 42(1):59-78


McCollum, L. (research in progress)





-Hansen Canyon, Wellsville Mountains, Box Elder Co., Utah

-Antimony Canyon, Wellsville Mountains, Box Elder Co., Utah

-Miners Hollow, Wellsville Mountains, Box Elder Co., Utah

-Idaho (Spence Gulch, near Liberty)


*researched and compiled by Linda McCollum, James Cook, Kevin D. Brett

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