17 Feb
Gull River Fm., Black River Grp., upper Ordovician, southeastern Ontario

Bathyurus extans, Gull River Fm., Black River Grp., Upper Ordovician, Southeast Quebec

Bathyurus extans, Gull River Fm., Black River Grp., Upper Ordovician, Southeast Quebec


16 Feb


14 Feb

Bufoceraurus sp., Bobcaygeon Fm., Victoria County, Ontario


The largest of the Cheirurid trilobites of eastern North America, this genus is found in the Bobcaygeon and Verulam Trenton Group of the upper Ordovician of Ontario.

Near Ottawa, Ontario. Author’s collection.

Lateral preservation on a plate with multiple Flexicalymene sp., Hastings County Ontario. Author’s collection

Ottawa, Ontario. Author’s collection.

Near Ottawa, Ontario. Found by the author, prepared by Jerry Kloc. Now in the collection of the Royal Ontario Museum.

Near Ottawa, Ontario. Private collection.

Found near Ottawa. Note deformed geenal spine on the top specimen.

Author’s colelction.


23 Oct


An Asaphid trilobite that is very common in the Cobourg Fm. and found in almost all strata above the base of the Gull River Fm. This trilobite could be quite large: specimens found at Colborne, Ontario, show Isotelus latus could grow to at least 18 inches. Isotelus maximus in the younger Cincinnatian (equiavalent to the Georgian Bay Fm in Central Ontario, the Russell Fm in the Ottawa area and the Nicolet Fm. in Quebec) could reach similar sizes. Isotelus rex, found in Ordovician rocks near Churchill, Manitoba, is the largest complete trilobite ever found.


Isotelus platycephalus, Gull River Fm.


Isotelus (undescribed, similar to Isotelus iowensis), Ottawa



Multiple specimen from same strata as above trilobite



8″ dorsal specimen from same strata. Note the forked hypostome (mouth plate)



Isotelus ottawensis, near Picton, Ontario




Isotelus gigas, Port Hope, Ontario



Isotelus gigas, near Picton, Ontario


23 Oct

Triarthrus is a common trilobite in the “Billings Shale” of eastern Ontario and the Lorraine Shales of New York State and Quebec.198507_10150152281896291_5380657_n