Thunder Bay Limestone

{{Infobox rockunit|name=Thunder Bay Limestone|image=|caption=|type=Geological formation|age={{fossil range|Givetian|Givetian|Middle Devonian (Givetian)}}|period=Devonian|prilithology=limestone|otherlithology=shale|namedfor=Thunder Bay (Michigan)|namedby=|region=Michigan|country=United States|coordinates=|unitof=Traverse Group|subunits=Partidge Point Member, Potter Farm Member, and Norway Point Member|underlies=Kettle Point Formation and Squaw Bay Limestone|overlies=Potter Farm Formation|thickness={{Convert|4.88|m|ft}}|extent=|area=|map=|map_caption=}}Thunder Bay Limestone is a geologic formation in Michigan that preserves fossils dating back to the Middle Devonian and is the uppermost formation of the Traverse Group.{{Citation |last1=Gutschick |first1=Raymond C. |title=Upper Devonian biostratigraphy of Michigan Basin |date=1991 |pages=155–180 |url=https://doi.org/10.1130/spe256-p155 |access-date=2024-12-15 |publisher=Geological Society of America |last2=Sandberg |first2=Charles A.|series=Geological Society of America Special Papers |volume=256 |doi=10.1130/spe256-p155 |isbn=0-8137-2256-X |url-access=subscription }}

Description

File:An_examination_of_the_Devonian_fishes_of_Michigan_fig-1-full.png

The name for the formation originates from the description of strata near the "south cape of Thunder Bay" by C. C. Douglas in 1841, this area also represents the type locality of the formation. Due to negligence by multiple later workers, the area was later referred to as the Partridge Point Formation by Warthin & Cooper in 1935. It wasn't until 1943 that Warthin & Cooper would rename the formation back to its original name.Devonian strata of Alpena and Presque Isle Counties, Michigan

The type locality (Locality 30-8-11 SE) is the largest outcrop of the formation, exposing six units that have a total depth of about 4.8 meters. These units are largely made from light-colored limestones though the bottom-most unit has bluish limestone. The most unique unit would be unit 3 which mostly is made up of grey shales that grades into granular limestone at the surface.

The environment that the formation represents is a shallow carbonate platform with large amounts of coral and shelly fauna. Later formations show an increase in depth as water levels raised in the Eastern Interior seaway. Over time, the seaway would develop a stratified water column. Eventually, younger formations, like the Squaw Bay limestone, would show a deep basin environment.{{Citation |last1=Gutschick |first1=Raymond C. |title=Late Devonian history of Michigan Basin |date=1991-01-01 |work=Early Sedimentary Evolution of the Michigan Basin |pages=0 |editor-last=Catacosinos |editor-first=Paul A. |url=https://pubs.geoscienceworld.org/gsa/books/edited-volume/393/chapter-abstract/3797570/Late-Devonian-history-of-Michigan-Basin?redirectedFrom=fulltext |access-date=2024-12-15 |publisher=Geological Society of America |doi=10.1130/spe256-p181 |isbn=978-0-8137-2256-6 |last2=Sandberg |first2=Charles A. |editor2-last=Daniels |editor2-first=Paul A., Jr.|url-access=subscription }}

Paleobiota

= Anthozoa =

class="wikitable"

!Genus

!Species

!Notes

!Image

Antholites{{Cite journal |last=Stumm |first=Erwin C. |date=1950 |title=Corals of the Devonian Traverse Group of Michigan. Part III, Antholites, Pleurodictyum, and Procteria |journal=Contributions from the Museum of Paleontology, University of Michigan |volume=8 |issue=8}}

|A. alpenensis

Aulacophyllum{{Cite journal |last=Stumm |first=Erwin C. |date=1963 |title=Corals of the Traverse Group of Michigan Part XI, Tortophyllum, Bethanyphyllum, Aulacophyllum, and Hallia |journal=Contributions from the Museum of Paleontology the University of Michigan |volume=18 |issue=8}}

|A. hemicrassatum

Alveolites{{Cite journal |last=Stumm |first=Erwin C. |date=1951 |title=Check list of fossil invertebrates described from the middle Devonian Traverse group of Michigan |journal=Contributions from the Museum of Paleontology University of Michigan |volume=9 |issue=1}}

|A. sp

Bethanyphyllum

|B. geniculatum

Cylindrophyllum{{Cite journal |last1=Ehlers |first1=GEORGE M. |last2=Stumm |first2=ERWIN C. |date=1949 |title=Corals of the Devonian Traverse Group of Michigan. Part II. Cylindrophyllum, Depasophyllum, Disphyllum, Eridophyllum, and Synaptophyllum |journal=Contributions from the Museum of Paleontology University of Michigan |volume=8 |issue=3}}

|C. grabaui

Cystiphylloides{{Cite journal |last=Stumm |first=Erwin C. |date=1962 |title=Corals of the Traverse Group of Michigan Part VII, The Digonophyllidae |journal=Contributions from the Museum of Paleontology the University of Michigan |volume=17 |issue=9}}

|C. americanum elongatum

|File:Cystiphylloides_sp.jpg

Drymopora

|D. sp.

rowspan="3" |Favosites{{Cite journal |last1=Stumm |first1=Erwin Charles |last2=Tyler |first2=John H. |date=1964 |title=Corals of the Traverse Group of Michigan Part XII, The Small-Celled Species of Favosites and Emmonsia |journal=Contributions from the Museum of Paleontology the University of Michigan |volume=19 |issue=3}}

|F. mammillatus

| rowspan="3" |File:FavositesOrdovicianIndiana.jpg

F. placentus

F. romingeri

Heterophrentis

|H. sp.

Hexagonaria{{Cite journal |last=Stumm |first=Erwin C. |date=1970 |title=Corals of the Traverse Group of Michigan Part 13, Hexagonaria |journal=Contributions from the Museum of Paleontology, University of Michigan |volume=23 |issue=5}}

|H. potterensis

|File:2011-07-09_gasometer_36.JPG

Platyaxum

|P. sp.

Stereohma{{Cite journal |last=Stumm |first=Erwin C. |date=1962 |title=Corals of the Traverse Group of Michigan Part VIII, Stereolasma and Heterophrentis |journal=Contributions from the Museum of Paleontology the University of Michigan |volume=17 |issue=10}}

|S?. sp. A.

Syringopora

|S. sp.

|File:Syringopora_coral_KGS.jpg

rowspan="5" |Trachypora{{Cite journal |last1=Stumm |first1=Erwin C. |last2=Hunt |first2=Allen S. |date=1958 |title=Corals of the Devonian Traverse Group of Michigan. Part V. Trachypora |journal=Contributions from the Museum of Paleontology University of Michigan |volume=14 |issue=11}}

|T. alternans

| rowspan="5" |

T. dendroidea

T. perreticulata

T. proboscidialis

T?. reticulata

= Brachiopoda =

class="wikitable"

!Genus

!Species

!Notes

!Image

Athyris

|A. sp

|File:Athyris_concentrica_brachial_valve.jpg

Atrypa

|A. sp

|File:Atrypa_reticularis00.gif

Camarotoechia

|C. sp

|File:Camarotoechia_ANSP.jpg

Chonetes

|C. sp

|File:Chonetes_gracilis_internal_mould_inmatrix_frontal.jpg

rowspan="2" |Cranaena

|C. lincklaeni

| rowspan="2" |File:Cranaena.jpg

C. romingeri

rowspan="2" |Cytina{{Cite journal |last1=Pitrat |first1=Charles W. |last2=Keyes |first2=Scott W. |date=1978 |title=Spiriferid brachiopods from the Traverse Group of Michigan: Cyrtinacea |journal=Journal of Paleontology |volume=52 |issue=2}}

|C. hamiltonensis

| rowspan="2" |

C. sp

Meristella

|M. sp

|File:Meristella_two_views.png

Mucrospirifer

|M. sp

|File:Mucrospirifer_mucronatus_Silica_Shale.JPG

Pentamerella

|P. sp

Orthospirifer{{Cite journal |last=Pitrat |first=Charles W. |date=1977 |title=Spiriferid Brachiopods from the Traverse Group of Michigan: Orthospirifer |journal=Journal of Paleontology |volume=51 |issue=2}}

|O. traversensis

= Bryozoa =

class="wikitable"

!Genus

!Species

!Notes

!Image

Cyphotrypa

|C?. unua

Euspilipora

|E. serrata

rowspan="4" |Fenestrellina

|F. compacta

| rowspan="4" |

F. longispinosa

F. nodicula

F. variifenestrula

Fistuliphragma

|F. spinulifera

rowspan="4" |Fistulipora

|F. acervulosa

| rowspan="4" |File:Fistulipora_neglecta_fossil_bryozoan_(Silurian;_near_Waldron,_Indiana,_USA)_(15209549272).jpg

F. corrugata

F. stellifera

F. sulcata

rowspan="5" |Hederella

|H. cirrhosa

| rowspan="5" |

H. compacta

H. delicatula

H. persimilis

H. rugosa

rowspan="2" |Lioclema

|L. incompositum

| rowspan="2" |

L. minutum

Polypora

|P. modesta

|File:Polypora_incepta.jpg

rowspan="2" |Scalaripma

|S. approximata

| rowspan="2" |

S. separata

Semicoscinium

|S. approximatum

|File:Semicoscinium_tenuiceps_(fossil_bryozoan)_(Lockport_Dolomite,_Middle_Silurian;_Rockford_Stone_Company_Quarry,_Rockford,_Ohio,_USA).jpg

Sulcoretepora

|S. hadmiltonensis

|File:Sulcoretepora_deissi_-_National_Museum_of_Nature_and_Science,_Tokyo_-_DSC07728.JPG

= Conodonta =

class="wikitable"

!Genus

!Species

!Notes

!Image

rowspan="3" |Icriodus{{Cite journal |last=Orr |first=R. William |date=1971 |title=Conodonts from Middle Devonian Strata from the Michigan Basin |journal=Indiana Geological Survey Bulletin |volume=45}}

|I. cymbiformis

| rowspan="3" |

I. expansus

I. latericrescens latericrescens

Polygnathus

|P. varcus

|File:Polygnathus_Pa_elements.png

= Echinodermata =

class="wikitable"

!Genus

!Species

!Notes

!Image

Aorocrinus

|A. cassedayi

Atractocrinus{{Cite journal |last=Kirk |first=Edwin |date=1948 |title=Two new inadunate crinoid genera from the Middle Devonian [Ont., Iowa, Michigan, New York]. |journal=American Journal of Science |volume=246 |issue=11|page=701 |doi=10.2475/ajs.246.11.701 |bibcode=1948AmJS..246..701K }}

|A. campanulatus

Botryocrinus{{Cite journal |last=Kesling |first=Robert V. |date=1963 |title=Occurrence and variations of Botryocrinus thomasi Laudon in the Thunder Bay Limestone of Michigan |journal=Contributions from the Museum of Paleontology, University of Michigan |volume=18 |issue=15}}

|B. thomasi

|File:A_guide_to_the_fossil_invertebrate_animals_in_the_Department_of_geology_and_palaeontology_in_the_British_museum_(Natural_history)_(1907)_(14756242876).jpg

Codaster

|C. gracile

Corocrinus{{Cite journal |last=Kesling |first=Robert Vernon |date=1964 |title=Two new crinoids of the family Periechocrinitidae from the Middle Devonian Thunder Bay Limestone of Michigan |journal=Contributions from the Museum of Paleontology, University of Michigan |volume=19 |issue=11}}

|C. pettyesi

|File:Corocrinus_nodosus_(fossil_crinoid)_(Silica_Formation,_Middle_Devonian;_quarry_northwest_of_Paulding,_Ohio,_USA)_1_(48318602701).jpg

Dactylocrinus

|D. alpena

rowspan="3" |Dolatocrinus{{Cite journal |last1=Kesling |first1=Robert Vernon |last2=Mintz |first2=Leigh W. |date=1963 |title=Dolatocrinus and Stereocrinus, its junior synonym |journal=Contributions from the Museum of Paleontology, University of Michigan |volume=18 |issue=14}}

|D. asterias

| rowspan="3" |

D. barrisi

D. triangulatus

Euryocrinus

|E. barrisi

Gennaeocrinus

|G. romingeri

Lipsanocystis{{Cite journal |last=Stumm |first=Erwin C. |date=1955 |title=Three new species of the cystid genus Lipsanocystis from the Middle Devonian Traverse Group of Michigan |journal=Contributions from the Museum of Paleontology, University of Michigan |volume=12 |issue=6}}

|L. traversensis

rowspan="5" |Megistocrinus

|M. concavus

| rowspan="5" |

M. multidecoratus

M. nodosus

M. novus

M. tuberatus

rowspan="3" |Nucleocrinus

|N. elegans ?

| rowspan="3" |File:Nucleocrinus_elegans_(fossil_blastoids)_in_fossiliferous_calcareous_shale_(Silica_Formation,_Middle_Devonian;_quarry_near_Paulding,_Ohio,_USA)_(16978081199).jpg

N. meloniformis

N. obovatus

rowspan="4" |Pentremitidea

|P. americana

| rowspan="4" |File:Pentremitidea_pailleti.jpg

P. bassleri

P. bassleri hastula

P. milwaukeensis

rowspan="3" |Stereocrinus

|S. barrisi

| rowspan="3" |

S. triangdatus

S. triangdatus lirata

rowspan="2" |Synbathocrinus{{Cite journal |last1=Kesling |first1=Robert Vernon |last2=Smith |first2=Raymond N. |date=1963 |title=The crinoid Synbathocrinus in the Middle Devonian Traverse Group of Michigan |journal=Contributions from the Museum of Paleontology, University of Michigan |volume=18 |issue=11}}

|S. matutinus

S. sp. cf. S. michiganensis

|File:Synbathocrinus_fossil_crinoid_(Burlington_Limestone,_Mississippian;_Missouri,_USA)_1_(17383990962).jpg

= Mollusca =

class="wikitable"

!Genus

!Species

!Notes

!Image

rowspan="2" |Cimitaria{{Cite journal |date=1986 |editor-last=Pojeta |editor-first=John |title=Devonian rocks and Lower and Middle Devonian pelecypods of Guangxi, China, and the Traverse Group of Michigan |url=https://doi.org/10.3133/pp1394ag |journal=Professional Paper |doi=10.3133/pp1394ag |issn=2330-7102}}

|C. recurva

| rowspan="2" |

C. sp

Modiomorpha

|M. mytiloides

Mytilarca

|M. cf. M. oviformis

|File:Mytilarca_cingulosa.jpg

Plethomytilus

|P. sp

= Placodermi =

class="wikitable"

!Genus

!Species

!Notes

!Image

Ptyctodus{{Cite journal |last1=Stack |first1=Jack |last2=Sallan |first2=Lauren |date=2018 |title=An examination of the Devonian fishes of Michigan |journal=PeerJ |volume=6|pages=e5636 |doi=10.7717/peerj.5636 |doi-access=free |pmc=6151260 }}

|P. sp

|File:Ptyctodus ferox.jpg

= Stromatoporoidea =

class="wikitable"

!Genus

!Species

!Notes

!Image

Stromatopora

|S. sp.

|File:Stromatopora_sp.jpg

= Tentaculita =

class="wikitable"

!Genus

!Species

!Notes

!Image

Tentaculites

|T. sp

|File:Tentaculites_2.jpg

= Trilobita =

class="wikitable"

!Genus

!Species

!Notes

!Image

Dechenella{{Cite journal |last=Strumm |first=Erwin. C |date=1953 |title=Trilobites of the Devonian Traverse group of Michigan |journal=Contributions from the Museum of Paleontology University of Michigan |volume=10 |issue=6}}

|D. reimanni

|File:Dechenella_fossil_from_the_Devonian_period,_Iran.jpg

Dipleura

|D. dekayi

|File:Dipleura_dekayi_2.jpg

Greenops

|G. alpenensis

|File:Greenops_widderensis.jpg

Phacops

|P. iowensis

|File:Phacops_rana.jpg

Proetus