Nine clay specimens taken from various sites in Egypt and belonging to different epochs have been examined by thermogravimetry (TG), differential thermal analysis, infrared, and x-ray diffraction for their characterization. A method is proposed using essentially TG data to differentiate between kaolinitic and non-kaolinitic clays. The content of some trace elements-namely, iron, potassium, and manganese-in the clays can be used to identify kaolins. No correlation could be observed between the epoch of deposition and the nature of the clay mineral content. See also AATA 12-136 and 14-395 for earlier work on the subject. -- AATA