A New Occurrence of Protichnites in Potsdam Group Sandstone near Kingston, Ontario

Below I’ve provided photographs of slabs of sandstone bearing the trace fossil Protichnites that I collected on July 4^th with Wayne Jackson. The specimens were collected from a quarry in an outlier that has been mapped as Potsdam Group, and is considered to be Cambrian in age.  The specimens belong to the Nepean (Keeseville) formation of the Potsdam Group.

The first two photos show three specimens that were offered to the Miller Museum of Geology at Queen’s University and were picked up by the Museum Curator on July 5^th. The other photographs are closeup shots of the specimens, some as they were awaiting pickup and others as they were found.  

Each of the Protichnites trackways is roughly 16 to 17 cm ( 6 ½ inches) wide and cuts across ripple marks in the sandstone. In the first two photos the slabs at the top and bottom are the natural cast in the sediment laid down on top of the original trackway, while the middle slab records the original trackway.   The Protichnites trace fossil is a trackway that is believed to have been made by a creature with multiple legs and a tail, with the central furrow in the trackway being a tail drag mark. (The furrow appears as a ridge in the cast.)  In the  specimens in the photographs the central furrow is 3 to 4 cm wide and some of the footprints are up to 1 cm in diameter.

This is a new occurrence of Protichnites in the Potsdam Group Sandstones and was found near Kingston, Ontario.

I should thank my wife for meeting me for coffee on July 4^th and encouraging me to take the rest of the afternoon off to go look for fossils. Without her encouragement I might have stayed in the office and worked.


Christopher Brett
Perth, Ontario

(July 12th, 2013 Addendum :   Since posting the above I have been contacted by a friend, Dave Lowe, who is studying the Potsdam Group, who has told me that in addition to the Chippewa Bay member this outlier also exhibits a younger facies similar to the Nepean Formation near Ottawa, with an angular erosional unconformity between the two.   I was wrong in assigning the specimens that I collected to the Covey Hill Formation.  [ April 26, 2023, Addendum:] When I originally wrote  this posting I relied on Sanford and Arnott (2010) and identified the sandstone as the Chippewa Bay Member, Covey Hill Formation, of the Potsdam Group.  In July, 2013 Dave Lowe told me that the outlier also exhibits a younger facies similar to the Nepean Formation near Ottawa.   Now I would clearly identify the sandstone where the specimens were found as Nepean (Keeseville) formation as I found Protichnites, Diplichnites, Climactichnites and the basal, U shaped, part of Arenicolites or Diplocraterion  fossils in this sandstone.    ]