AbstractA significant working difference between the mode and type is seen to lie in the greater tendency of the former to reappear on different time levels. In part, this is because more opportunity exists for the chance reduplication of an isolated feature than for a group of integrated attributes. Consideration of the flange-and-ridge and the everted-rim traditions in Maya ceramics focuses attention on additional factors which may help to account for the reappearance of modes. The possibility is recognized of refuge zones where traits continued, later to diffuse back to the centers of the investigation. Primary theoretical consideration is given to the modification of traits through the elaboration of traditions and the possibility that this process sometimes led to the reinvention or resurgence of once popular forms. Such a process is based on the potter's wish to create something slightly different while working within the technico-stylistic bounds of a tradition. This may occasionally lead to a recombination of elements that approximate older forms (low level reinvention) or to a twist that imparts fresh interest to a dying form — hence renewed recognition of the mode by the investigator following its complete disappearance in his archaeological samples.