Gull River Formation
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The Gull River Formation is a geological formation of Middle Ordovician age (Caradoc Stage), which outcrops in Ontario, Canada.[1] Lithologically, the formation is dominated by light grey to brown limestones and greenish gray dolomites with thin shale and sandstone interlayers.[2][3]
TypeFormation
Unit of
Underlies
- Bobcaygeon Formation
- Coboconk Formation
OverliesShadow Lake Formation
| Gull River Formation | |
|---|---|
| Stratigraphic range: Caradoc ~ | |
Gull River Formation exposed along the shore of Lake St. John, Ramara | |
| Type | Formation |
| Unit of | |
| Underlies |
|
| Overlies | Shadow Lake Formation |
| Lithology | |
| Primary | Limestone, dolomite |
| Other | Shale, sandstone |
| Location | |
| Region | Ontario New York Pennsylvania |
| Country | Canada United States |
| Type section | |
| Named for | Gull River |
| Named by | V. J. Okulitch |
| Year defined | 1939 |
Fossil content
Invertebrates
Chelicerates
| Chelicerates reported from the Gull River Formation | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| Lunataspis | L. borealis | Upper Member, Kingston, Ontario.[4] | 3 specimens (1 adult & 2 juveniles or subadults).[4] | A horseshoe crab. | |
Flora
Acritarchs
| Acritarchs reported from the Gull River Formation | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| Dicommopalla | D. rissae | Southern Ontario.[5] | Also found in the Bobcaygeon Formation. | ||
