The initial paper in this series (Littmann 1957, American Antiquity, Vol. 23, No. 2, pp. 135-40) presented a systematic approach to the study of ancient building elements such as mortars, plasters, and stuccos, and set forth the bases upon which the work was undertaken. It also included studies on steps of the prebrick period of Temple IV at Comalcalco, Tabasco, Mexico, in which it was demonstrated that a building unit comprising a monolithic limeaggregate structure covered with a thin, limebased wash coat followed by a thicker coat of plaster was used. Such a unit appeared to have been used in both the original structure and subsequent additions or modifications throughout the prebrick period.