Gun River Formation
Geologic formation in Quebec, Canada
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The Gun River Formation is a geologic formation in Quebec. It preserves fossils dating back to the early Silurian period.
Sub-units
- Lachute Member
- Innomée Member
- Sandtop Member
- Macgilvray Member
UnderliesMenier Formation[1]
OverliesMerrimack Formation[1]
| Gun River Formation | |
|---|---|
| Stratigraphic range: Early Silurian (Llandovery) | |
| Type | Geological formation |
| Sub-units |
|
| Underlies | Menier Formation[1] |
| Overlies | Merrimack Formation[1] |
| Thickness | 85 to 100 meters[1] |
| Location | |
| Region | Quebec |
| Country | Canada |
| Type section | |
| Named by | Schuchert and Twenhofel[1] |
| Year defined | 1910[1] |
Description
The formation is divided into 4 members (from the base up): the Lachute, Innommée, Sandtop and Macgilvray members. The formation was deposited some 40–80 km offshore from the stable Laurentian craton, underwater at depths of 30 to 60 meters.[1]
Fossil content
Vertebrates
Color key
|
Notes Uncertain or tentative taxa are in small text; |
| Conodonts | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| Anticostiodus | A. fahraeusi | Anticosti Island.[2] | |||
| A. boltoni | Anticosti Island.[2] | ||||
| Icriodella | I. deflecta | Probably instead belongs to the Jupiter Formation.[1] | |||
Invertebrates
| Brachiopods | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| Brachyprion | Sandtop and Macgilvray Members.[1] | A strophomenid. | |||
| Coolinia | Sandtop and Macgilvray Members.[1] | ||||
| Fenestrirostra | F. glacialis | Lowermost part of the formation.[3] | A rhynchonellidalso found in the Merrimack Formation. | ||
| F. pyrrha | Lachute Member.[1] | A rhynchonellid. | |||
| 'Gotatrypa' | 'G.' sp. | Innommée Member.[1] | |||
| Hyattidina | Sandtop to Macgilvray Members.[1] | An athyrid. | |||
| Joviatrypa | Uppermost Macgilvray Member.[1] | ||||
| Kulumbella | K. xacta | Upper Macgilvray Member.[4][5] | A pentamerid. | ||
| Mendacella | Innommée Member.[1] | A dalmanellid. | |||
| Meristina | Innommée Member.[1] | ||||
| Pentamerus | P. palaformis | Top of the formation (uppermost Macgilvray Member).[1][4] | Also found in the Jupiter Formation. | ||
| Stegerhynchus | [1] | ||||
| Stricklandia | S. gwelani | Top of the formation (Macgilvray Member).[1][4] | Also found in the Jupiter Formation. | ||
| S. sp. | Innommée Member.[4] | A509 (7 broken valves on a slab).[4] | Also found in the uppermost Merrimack Formation. | ||
| Sypharatrypa | S. sp. | Innommée Member.[1] | |||
| Bryozoans | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| Phaenopora | P. superba | Also found in the Becscie Formation.[6] | |||
| Ptilodictya | P. canadensis | USNM 143039.[6] | |||
| P. sulcata | USNM 143039, 143050; YPM 3063/98, 3063/104.[6] | ||||
| Corals | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| Acidolites | A. arctatus | [7] | A heliolitid. | ||
| Brachyelasma | [1] | ||||
| Crassilasma | [1] | ||||
| Helicelasma | [1] | ||||
| Palaearaea | Cap aux Goélands (Uppermost Macgilvray Member).[1] | Small colonies.[1] | The only rugosan coral known from the formation, also found in the Menier formation. | ||
| Paleofavosites | P. capax | Multiple colonies.[8] | A tabulate coral. | ||
| Graptolites | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| Paraclimacograptus | P. cf. innuitus | Deeper water facies of the Sandtop Member.[1] | |||
| Sponges | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| Camptodictyon | [1] | A stromatoporoid. | |||
| Clathrodictyon | [1] | A stromatoporoid. | |||
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