| Guelph Formation | |
|---|---|
| Stratigraphic range: Silurian | |
 Stromatolite from the Guelph Formation | |
| Type | Sedimentary |
| Underlies | Vernon, Lockport Group |
| Overlies | Eramosa Member |
| Thickness | 160 feet[1] |
| Lithology | |
| Primary | Dolomite |
| Location | |
| Region |  New York |
| Country |  United States |
| Type section | |
| Named for | Guelph, Ontario |
| Named by | William Edmond Logan[1] |
The Guelph Formation is a geologic formation in New York and in Ontario, Canada. It preserves fossils dating back to the Silurian period.[2]
- ^ a b Logan, W.E., Murray, A., Hunt, T.S., and Billings, E., 1863. Geology of Canada. Report of Progress from its Commencement to 1863; Geological Survey of Canada, 983 p. [accompanied by an Atlas of Maps and Sections.] doi:10.4095/123563
- ^ Guelph, USGS, National Geologic Map Database, Geolex — Unit Summary