Four Mile Dam Formation
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Geological feature in Michigan USA
| Four Mile Dam Formation | |
|---|---|
| Stratigraphic range: Middle Devonian (Givetian)[1] | |
 Vertebrate remains from the Four Mile Dam Formation. | |
| Type | Geological formation |
| Unit of | Traverse Group[1] |
| Lithology | |
| Primary | Limestone |
| Location | |
| Region | Michigan |
| Country | United States |
| Type section | |
| Named by | Cooper & Warthin[2] |
| Year defined | 1941[2] |
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.
Vertebrates
Acanthodians
| Acanthodians reported from the Four Mile Dam Formation | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| 'Acanthodii' | Unidentified | "Two partial fin spines (JS 120, JS 121)".[1] | "Distinct from named acanthodians (Gyracanthus, Machaeracanthus, and Oracanthus) and chondrichthyans (Tamiobatis and Acondylacanthus) reported from Michigan".[1] |  | |
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
| Placoderms reported from the Four Mile Dam Formation | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| ?Macropetalichthys | ?M. sp. | "A partial head shield (32M)".[1] | A petalichthyid. |  | |
| ?Mylostoma | ?M. sp. | 39 specimens, including potential juveniles.[1] |  | ||
| 'Placodermi' | Unidentified | "One specimen of an armour plate (JS 4)".[1] |  | ||
| Protitanichthys | P. rockportensis | "One specimen of an armor fragment (JS 101)".[1] | A coccosteid. | ||
Invertebrates
Color key
|
Notes Uncertain or tentative taxa are in small text; |
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
| Sponges reported from the Four Mile Dam Formation | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| Anostylostroma | A. anacolumna | On Thunder Bay River.[6] | A stromatoporoid. | ||
Trilobites
| Trilobites reported from the Four Mile Dam Formation | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| Cordania | C. rara | [7] | |||
| Dechenella | D. (Monodechenella) macrocephala | [7] | Also found in the Hamilton Group. | ||
| D. (Basidechenella) rowi | [7] | Also known from the Hamilton Group. | |||
| Eldredgeops | E. rana | [7] | Originally reported as Phacops rana. Also found in the Hamilton, Hungry Hollow, Widder, Plum Brook, Prout, Ten Mile Creek, Alpena, Norway Point and Gravel Point formations. |  | |
| Greenops | G. aequituberculatus | Dock Street clay member.[7] | Also found in the Norway Point and Gravel Point formations. | ||
| G. traversensis | Dock Street clay member.[7] | Also found in the Gravel Point Formation. | |||
| Phacops | P. rana | [7] | Reassigned to the genus Eldredgeops. | ||
| Proetus | P. (Crassiproetus) traversensis | [7] | Also known from the Gravel Point Formation. | ||
See also
References
- 1 2 3 4 5 6 7 8 9 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.
- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 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.
- 1 2 3 4 5 Orr, R. William (1971). "Conodonts from Middle Devonian Strata from the Michigan Basin".
{{cite journal}}: Cite journal requires|journal=(help) - 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 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".
{{cite journal}}: Cite journal requires|journal=(help) - 1 2 3 4 5 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.
- 1 2 3 4 5 6 7 8 Stumm, Erwin (1953). "Trilobites of the Devonian Traverse Group of Michigan" (PDF). University of Michigan Press - Museum of Paleontology.
- Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Archived from the original on 25 March 2022. Retrieved 17 December 2021.
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