There can be cases of propositional memory that are not based on event memory even when the memory is due to one's experience of the event in question.  Last Christmas, I came to believe that my driveway was then icy; that's why I parked on the street.  My belief that my driveway was icy was formed on the basis of my perceiving the ice. But now that I recall the condition of my driveway, I don't base my belief on my event memory of the icy driveway.  I just remember that my driveway was icy.  On the other hand, there are cases where one does recall an event and form a new belief on the basis of a memory image. For example, if I were asked whether the ice on my driveway last Christmas was uniform, I might well call to mind a memory image of the driveway and see if it contains that information.  In this case, it seems, I am using event memory (i.e., memory of my seeing the driveway) to form a belief about the uniformity of the thickness of the ice.  There is a real sense, then, in which the belief that the ice's thickness was (say) uniform is not a memory belief in at least one legitimate sense of that term. There is surely a suitable way of thinking of memory beliefs that stipulates that only beliefs that have been formed at a prior time count as memory beliefs.