| Georgian Bay Formation | |
| Type: | Formation |
| Age: | Upper Ordovician (upper Maysvillian-lower Richmondian) |
| Period: | Ordovician |
| Region: | , |
| Country: | , |
| Underlies: |
|
| Overlies: | Blue Mountain Formation |
The Georgian Bay Formation is a geologic formation in Michigan and Ontario. It preserves fossils dating back to the Ordovician period. The type locality of the formation is on East Meaford Creek (previously called Workman Creek), south shore of Nottawasaga Bay, Georgian Bay.[1]
The formation consists of massive shale interbedded with siltstone/sandstone and limestone, with sub-horizontal bedding planes and widely spaced jointing.[2]
| Ichnotaxa | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| Paleodictyon | P. isp. A | Southern Ontario.[3] | 2 specimens, ROM 49424 and ROM 49624. | ||
| ?P. isp. B | Southern Ontario. | 1 specimen: ROM 49625. | |||
| Planolites | P. constriannulatus | Southern Ontario.[4] | |||
| Conodonts | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images | |
| Amorphognathus | A. ordovicicus | Lower part of the formation. | Also found in the Blue Mountain Formation. | |||
| Aphelognathus | A. grandis | Uppermost lower and upper members. | ||||
| A. politus | Lower part of the formation. | Also found in the Blue Mountain Formation. | ||||
| A. pyramidlis | Upper member. | |||||
| Belodina | B. confluens | Lower member at southern Georgian Bay. | ||||
| Coelocerondontus | C. trigonius | Lower part and Upper member of the formation. | ||||
| Decoriconus | D. fragilis | Upper member, Kagawong West Quarry. | ||||
| Drepanoistodus | D. suberectus | Lower part, uppermost lower and upper members of the formation. | Also found in the Blue Mountain Formation. | |||
| Gen. et. sp. indet. 1 | Upper member. | |||||
| Gen. et. sp. indet. 2 | Upper member, Kagawong West Quarry. | |||||
| Gen. et. sp. indet. 3 | Upper member, Kagawong West Quarry. | |||||
| Icriodella | I. prominens | Upper member, Kagawong West Quarry. | ||||
| I. superba | Lower part of the formation. | |||||
| Oulodus | O. robustus | Upper and lower members. | ||||
| O. ulrichi | Upper member. | |||||
| O. undulatus | Upper member. | |||||
| Ozarkodina | O. aff. O. hassi | Upper member, Kagawong West Quarry. | ||||
| Panderodus | P. gracilis | Lower part and upper member of the formation. | ||||
| P. aff. P. gracilis | Uppermost lower and upper members. | |||||
| P. staufferi | Lower part and upper member of the formation. | |||||
| Paroistodus | P. mutatus | Lower part of the formation. | Also found in the Blue Mountain Formation. | |||
| Periodon | P. grandis | Lower part of the formation. | Also found in the Blue Mountain Formation. | |||
| Phragmodus | P. undatus | Lower part and upper member of the formation. | Also found in the Blue Mountain Formation. | |||
| Plectodina | P. inclinata | Upper member at southern Georgian Bay. | ||||
| P. tenuis | Lower part and upper member of the formation. | |||||
| Pseudobelodina | P. inclinata | Upper member, Manitoulin Island. | ||||
| P. cf. P. kirki | Upper member, Manitoulin Island. | |||||
| P. microdentata | Manitoulin Island. | |||||
| P. quadrata | Upper member,Manitoulin Island. | |||||
| P. vulgaris vulgaris | Upper member,Manitoulin Island. | |||||
| Pseudooneotodus | P. beckmanni | Upper member, Kagawong West Quarry. | ||||
| Rhipidognathus | R. symmetricus | Upper part of the formation. | ||||
| Staufferella | S. falcata | Lower member at southern Georgian Bay. | ||||
| Walliserodus | W. curvatus | Upper member, Kagawong West Quarry. | ||||
| Zanclodus | Z. sp. | Upper member. | ||||