DEEP-WATER MARINE RUSOPHYCUS AND CRUZIANA FROM THE ORDOVICIAN LOTBINIERE FORMATION OF QUEBEC

Specimens of Rusophycus isp. and Cruziana isp. preserved on a slab col lected from talus of the late Middle Ordovician Lotbiniere Formation e xposed at Montmorency Falls, northeast of Quebec City, are figured and described. Post-Ordovician benthic trilobites, in marine scenarios th e presumed producers of such ichnotaxa, were restricted to generally s hallow-water ecological niches. Older trilobite tars inhabited a wide spectrum of environments, as also reflected in the occurrence of these ichnotaxa in the Lotbiniere Formation. Occurrence of these ichnotaxa in the Lotbiniere Formation, an undoubted basinal microflysch sequence , suggests that caution should be exercised, when occurring in isolati on, with respect to the palaeoenvironmental significance of these ichn otaxa, particularly in strata of Cambrian and Ordovician age. A non-ra ndom and, instead, an interpreted rheotactic orientation of Rusophycus suggests the existence of bottom currents during production of the tr aces.