The micropaleontological content (calpionellids, foraminifera, algae) of the samples collected during the CYAMAZ campaign (1982) from the Jurassic platform of the Mazagan Plateau allows their attribution to upper Malm (but the lowermost Neocomian cannot be excluded completely). These samples are compared with the DSDP Leg 79 ones and those coming from numerous onshore outcrop sections. That comparison shows that CYAMAZ samples are very similar (if not identical) to those of the top of the Jurassic platform in site 545 and in Western High Atlas sections.