| Attawapiskat Formation | |
|---|---|
| Stratigraphic range: Silurian | |
| Type | Geological formation |
| Location | |
| Region | Ontario |
| Country |  Canada |
The Attawapiskat Formation is a geologic formation in Ontario. It preserves fossils dating back to the Silurian period.
| Attawapiskat Formation | |
|---|---|
| Stratigraphic range: Silurian | |
| Type | Geological formation |
| Location | |
| Region | Ontario |
| Country | Canada |
The Attawapiskat Formation is a geologic formation in Ontario. It preserves fossils dating back to the Silurian period.
The Attawapiskat Formation encompasses a large portion of the Hudson Bay Basin. The formation remains visible from northern Ontario. A small portion of the formation does extend onto Nunavut territory.
It is widely believed that the formation originally deposited on a shallow rimmed shelf, followed by the development of barrier reefs into an nonlinear and uncoordinated "belt" around the Hudson Basin. Within the Hudson Bay Lowlands, the formation consists of dolomite and limestone rich in both coral and sponge. The formation is a haven for lithotopes, or media for sediments to deposit, with various types including:
The formation's depth reaches 62 meters at its deepest.
Color key
| Notes Uncertain or tentative taxa are in small text; |
| Brachiopods | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| Eocoelia | E. akimiskii | Inter-reef beds of the formation, on Akimiski Island. [1] | Over 300 specimens. [1] | ||
| Erilevigatella | E. euthylomata | [2] | |||
| Gypidula | G. akimiskiformis | [2] | |||
| Meristina | M. expansa | Ekwan River. [3] | Now deemed a junior synonym of Pentameroides septentrionalis. | ||
| Pentameroides | P. septentrionalis | Ekwan River and Attawapiskat River. [3] | |||
| Protanastrophia | P. repanda | [4] | |||
| Reticularia | R. septentrionalis | Ekwan River. [3] | Now deemed a junior synonym of Pentameroides septentrionalis. | ||
| Sapelnikovia | S. (=Reveroides) norfordi | Attawapiskat River. [3] | Now deemed a junior synonym of Pentameroides septentrionalis. | ||
| Trilobites | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| Acidaspis | A. sp. | Ekwan River at portage at Strong Rapids. [5] | |||
| Chiozoon | C. cf. cowiei | Ekwan River at portage at Strong Rapids. [5] | |||
| Dicranopeltis | D. sp. | Ekwan River at portage at Strong Rapids. [5] | |||
| Ekwanoscutellum | E. ekwanensis | Limestone Island, Severn River. [5] | "Nested stacks of mostly inverted (concave-up) large sclerites, the majority of which are pygidia". [6] | A scutelluine. | |
| Meroperix | M. aquilonarius | Ekwan River at portage at Strong Rapids. [5] | [6] | A scutelluine. | |
| Opoa | O. sp. | Ekwan River at portage at Strong Rapids. [5] | |||
| Perryus | P. severnensis | Limestone Island, Severn River. [5] | Several cranidia, pygidia and disarticulated exoskeletons. [5] | An encrinurid. |  |
| Stenopareia | S. sp. | Ekwan River at portage at Strong Rapids. [5] | [6] | An illaenid. | |
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