In a review of MacNeish"s Preliminary Archaeological Investigations in the Sierra de Tamaulipas, Mexico, Taylor claims that the sequence of phases is built largely on the evidence from Diablo Cave and that the method of analysis is based on the premise that one congery of artifacts equals one phase. MacNeish rejects these claims by reviewing the way in which he used single components and stratigraphically unmixed deposits from several sites to work out the phase sequence.