Geological feature in Michigan USA
The Four Mile Dam Formation , also called the Four Mile Dam Limestone , is a geologic formation in Michigan . It preserves fossils dating back to the middle Devonian period .
Stratigraphy of the Devonian deposits of the northern part of the Lower Peninsula of Michigan, showing the Four Mile Dam Formation[1]
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Fossil content
Vertebrates
Acanthodians
Conodonts
Conodonts reported from the Four Mile Dam Formation
Genus
Species
Presence
Material
Notes
Images
Acodina
A. formosa
[3]
Also found in the Detroit River , Traverse , Dundee , Bell , Alpena and Norway Point formations.
Belodella
B. devonicus
[3]
Also found in the Detroit River , Traverse , Antrim , Alpena and Norway Point formations.
Icriodus
I. latericrescens latericrescens
[3]
Also found in the Traverse , Bell , Ferron Point , Genshaw, Newton Creek, Alpena , Norway Point , Potter Farm and Thunder Bay formations.
Ozarkodina
O. willsi
[3]
Also found in the Detroit River , Traverse , Antrim , Dundee , Alpena and Norway Point formations.
Polygnathus
P. varcus
[3]
Also found in the Traverse , Antrim , Alpena , Norway Point and Thunder Bay formations.
Placoderms
Invertebrates
Color key
Notes Uncertain or tentative taxa are in small text ; crossed out taxa are discredited.
Brachiopods
Brachiopods reported from the Four Mile Dam Formation
Genus
Species
Presence
Material
Notes
Images
Douvillina
D. distans
Four Mile Dam, Thunder Bay River , Alpena County, Michigan .[4]
Also found in the Hungry Hollow Formation and Logansport Formation .
Leptalosia
L. radicans
Four Mile Dam, Thunder Bay River , Alpena County, Michigan .[4]
Also found in the Norway Point , Gravel Point , Alpena and Genshaw formations.
Longispina
L. emmetensis
Dock Street clay member.[4]
Also found in the Alpena Limestone and Gravel Point Formation .
Megastrophia
M. gibbosa
Four Mile Dam, Thunder Bay River , Alpena County, Michigan .[4]
Also found in the Hungry Hollow Formation and Logansport Formation .
Oligorhachis
O. oligorhachis
Four Mile Dam, Thunder Bay River , Alpena County, Michigan .[4]
Also found in the Gravel Point Formation .
Pentamerella
P. alpenensis
Dock Street clay member.[4]
Also found in the Alpena Limestone and Gravel Point Formation .
P. sp. C
Dock Street clay.[4]
A complete specimen.[4]
Protoleptostrophia
P. lirella
Dock Street clay member.[4]
Also found in the Norway Point Formation and Alpena Limestone .
Schuchertella
S. anomala
Possibly the Dock Street clay member.[4]
Also found in the Gravel Point Formation .
S. sp.
Four Mile Dam, Thunder Bay River , Alpena County, Michigan .[4]
Spinulicosta
S. mutocosta
Four Mile Dam, Thunder Bay River , Alpena County, Michigan .[4]
Also found in the Bell , Rockport Quarry , Ferron Point , Beebe School, Thunder Bay and Potter Farm formations.
Strophodonta
S. erratica
Dock Street clay member.[4]
Also found in the Alpena Limestone and Gravel Point Formation .
S. fissicosta
Dock Street clay member.[4]
Also found in the upper Gravel Point Formation .
S. nanus
Dock Street clay member.[4]
Also found in the Alpena Limestone and Gravel Point Formation .
S. paula
Dock Street clay member.[4]
Also found in the Alpena Limestone .
S. sp. B
Dock Street clay member and overlying crystalline limestone beds.[4]
Several specimens.[4]
Rhipidomella
R. penelope traversensis
Thunder Bay River , Alpena County, Michigan .[4]
Corals
Corals reported from the Four Mile Dam Formation
Genus
Species
Presence
Material
Notes
Images
Aulocystis
A. cooperi
[5]
Also found in the Plum Brook shale , Silica shale and Potter Farm Formation .
A. jacksoni
Dock Street clay member.[5]
Also found in the Silica Shale, Ferron Point Formation , Petoskey Formation, Hungry Hollow Formation , Widder Shale, Wanakah shale and Centerfield Limestone .
Aulopora
A. conferta
[5]
Also found in the Bell , Ferron Point , Gravel Point , Genshaw, Alpena , Potter Farm , Petoskey and Hungry Hollow formations.
A. gregaria
[5]
Also found in the Genshaw Formation, Alpena Limestone and Petoskey Formation.
Pachyphragma
P. concentricum
Dock Street clay member.[5]
Also found in the Ferron Point Formation , Gravel Point Formation and Alpena Limestone .
Gastropods
Gastropods reported from the Four Mile Dam Formation
Genus
Species
Presence
Material
Notes
Images
Anematina
A. conica
Upper limestone unit.[2]
An elasmonematid .
A. mellaria
Upper limestone unit.[2]
An elasmonematid , very rare in the Four Mile Dam Limestone.
Bembexia
B. (Genuspira) nodosa
Upper limestone unit.[2]
About 35 specimens.[2]
An eotomariid and the most abundant gastropod in the formation.
Dictyobembix
D. bella
Upper limestone unit.[2]
5 specimens.[2]
An eotomariid .
Mourlonia
M. lirata
Upper limestone unit.[2]
An eotomariid .
Murchisonia
M. (Murchisonia) subulata
Upper limestone unit.[2]
A murchisoniid , extremely rare in the formation.
Naticopsis
N. sp.
Upper limestone unit.[2]
A neritopsid , extremely rare in the formation.
Palaeoscurria?
P.? sp.
Upper limestone unit.[2]
3 poorly preserved ventral molds.[2]
A metoptomatid .
Platyceras
P. (Platyceras) bartlettense
Dock Street Clay Member.[2]
A platyceratid .
P. (Euthyrachis) indianense
Dock Street Clay Member.[2]
A platyceratid .
P. (Orthonychia) variabilis
Upper limestone unit.[2]
A platyceratid .
Pseudozygopleuridae ? Genus A
Genus A sp. A
Upper limestone unit.[2]
Relatively numerous steinkerns.[2]
Pseudozygopleuridae ? Genus B
Genus B sp. B
Upper limestone unit.[2]
One very poorly preserved steinkern with a few small shell patches (YPM 23684).[2]
Spiroscala
S. sp.
Upper limestone unit.[2]
One specimen (UMMP 47377).[2]
An eotomariid .
Straparollus
S. (Philoxene) sp.
Upper limestone unit.[2]
3 poorly preserved specimens.[2]
An euomphalid .
Trepospira
T. (Angyomphalus) bella
Upper limestone unit.[2]
A raphistomatid , very rare in the Four Mile Dam Limestone.
Turbinilopsis
T. anacarina
Upper limestone unit.[2]
Abundant specimens.[2]
An anomphalid .
Sponges
Trilobites
See also
References
^ a b c d e f g h i Stack, Jack; Sallan, Lauren (2018-09-20). "An examination of the Devonian fishes of Michigan" . PeerJ . 6 (2). doi :10.7717/peerj.5636 . PMC 6151260 .
^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa Tyler, John H. (1965). "Gastropods from the Middle Devonian Four Mile Dam Limestone (Hamilton) of Michigan" . Journal of Paleontology . 39 (3): 341–349. ISSN 0022-3360 .
^ a b c d e Orr, R. William (1971). "Conodonts from Middle Devonian Strata from the Michigan Basin" .
^ a b c d e f g h i j k l m n o p q r s Imbrie, John (1959). "Brachiopods of the Traverse group (Devonian) of Michigan. Part 1, Dalmanellacea, Pentameracea, Strophomenacea, Orthotetacea, Chonetacea, and Productacea. Bulletin of the AMNH ; v. 116, article 4" .
^ a b c d e Watkins, J. Lloyd (1959). "Middle Devonian Auloporid Corals from the Traverse Group of Michigan" . Journal of Paleontology . 33 (5): 793–808. ISSN 0022-3360 .
^ Tyler, John H. (1964). "Anostylostroma anacolumna n. sp. from the Four Mile Dam Limestone (Hamilton), Alpena County, Michigan" . Journal of Paleontology . 38 (5): 885–886. ISSN 0022-3360 .
^ a b c d e f g h Stumm, Erwin (1953). "Trilobites of the Devonian Traverse Group of Michigan" (PDF) . University of Michigan Press - Museum of Paleontology .
This page was last edited on 27 April 2024, at 08:19