Guelph Dolomite of Lockport Group (NY*,OH)
Guelph Dolomite of Niagara Group (MI)
Guelph Formation (PA)
late Silurian (Ludlow)*
Exposures in neighborhood of Galt and Guelph, Ontario, Canada (Logan, 1963).
Appalachian basin*
Michigan basin
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).