During micropaleontological analysis of 15 wells in the Jeanne d'Arc Basin, large numbers of spumellarian radiolarians were found to be present in Paleocene to Lower Eocene sections in most sites. This event coincides with the deposition of the prodeltaic South Mara unit, a sandy/silty member of the otherwise shaly Banquereau Formation. The restricted range of these taxa within this interval suggests that their preservation may have been a function of the higher sedimentation rate represented by the South Mara unit. At least five different taxa appear in the interval, based on gross morphology. These are largely similar or identical to coeval types described and illustrated in the literature from the nearby DSDP Site 384 and some North Sea locations.