There are few existing studies of contemporary Yuman ceramics in Baja California, and past research has primarily focused on how the craft has been ìwesternizedî since the Spanish mission period. Although innumerable ceramic traditions were practiced in Mexico prior to the arrival of the Spanish, it is not usually possible to trace the persistence of this craft through the transition from a semi-nomadic subsistence pattern to a more sedentary lifestyle; it is possible with Yuman ceramics. The author has developed a new method employing the vesicular or Egyptian rectangle to measure vessels and demonstrate diachronic and synchronic changes in the relative height and variety of forms. The associated theory holds that these changes correspond to the decreasing mobility, or increased sedentism, of Yuman peoples. Independent of the undeniable western influences on Yuman ceramics, this method shows that the proportional height of vessels increased with the persistence of this craft through time.