Ellsaspis Rasetti, 1945 occurs in a thin intraclast granule and echinoderm hash packstone in continental slope facies at Ville Guay. Presence of an anterior median glabellar node and assignment of a previously unrecognized pygdium to the type species support its classification as an endymioniine trilobite. Associated conodonts of the platform margin Juanognathus biofacies, a chitinozoan, and shelf-derived orthids indicate a correlation with the middle Arenigian and upper Canadian. Association of the conodonts Prioniodus evae and P. elegans precludes a precise correlation with the condensed sequences of the Baltic Basin.