Guelph Formation

{{Short description|Geological formation in New York and in Ontario, Canada}} {{Infobox rockunit | name = Guelph Formation | image = Guelph Formation stromatolite.jpg | caption = Stromatolite from the Guelph Formation | type = Sedimentary | age = Silurian | prilithology = Dolomite | otherlithology = | namedfor = Guelph, Ontario | namedby = William Edmond Logan<ref name=logan1863>Logan, W.E., Murray, A., Hunt, T.S., and Billings, E., 1863. Geology of Canada. [https://archive.org/details/reportofprogress00geolrich/page/n7/mode/2up 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</ref> | region = New York | country = United States | coordinates = | unitof = | subunits = | underlies =Vernon, Lockport Group | overlies =Eramosa Member | thickness =160 feet<ref name=logan1863/> | extent = | area = | map = | map_caption = }}

The '''Guelph Formation''' is a geologic formation in New York and in Ontario, Canada. It preserves fossils dating back to the Silurian period.<ref>[https://ngmdb.usgs.gov/Geolex/Units/Guelph_1916.html Guelph], USGS, National Geologic Map Database, Geolex — Unit Summary</ref>

==Fossils== Fossils within the formation include:<ref name=logan1863/> *''Pentamerus occidentalis'' (Hall) *''Megalomus canadensis'' (Hall) *''Murchisonia bivittata'' (Hall) *''M. macrospira'' (Hall) *''M. boydii'' (Hall) *''M. logani'' *''M. longispira'' *''M. uvittata'' *''M. turritiformis'' *''M. tullia'' *''Subulites ventricosus'' (Hall) *''Pleurotomaria solaroides'' (Hall) *''P. elora'' (Billings) *''P. galtensis'' (Billings) *''P. mora'' *''Cyclonema sulcata'' (Hall) *''C. galtensis'' *''C. thysbe'' *''C. psyche'' *''C. depressa'' *''Holopea guelphensis'' (Billings) *''Bellerophon angustata'' (Hall) *''Favosites gothlandica'' *''F. polymorpha'' *''Halysites catenulatus'' *''Columnaria galtensis'' *''Obolus sp.'' *''Orikoceras sp.'' *''Orthoceras darwini'' *''Cyrtoceras arcticameratum'' *''C. Jonesi'' *''Phragmoceras hector'' *''Calymene blumenbachii'' *''Diphyphyllum irregulare'' *''Amplexus laxatus'' *''Rhynchonella sp.'' *''Athyris sp.''

==References== {{reflist}}

Category:Silurian geology of New York (state) Category:Geologic formations of New York (state) Category:Silurian Ontario Category:Geologic formations of Ontario