Numeric age assessments of organic material encapsulated by rock varnish present on stone lintels of two “puquios” in the Nasca region of the south coast of Peru indicate a Precolumbian age. Accelerator mass spectrometry radiocarbon analyses at the Isotrace Laboratory revealed ages of cal A. D. 560(620)650 and cal A. D. 600(640)660 (1 sigma). These calibrated measurements are considered to be appropriate in the context of the archaeological settlement pattern data for the region. As well, the written documents of the colonial period neither confirm nor deny the presence of the puquios. Three assumptions are inherent in the acceptance of these dates: (1) AMS 14C dating and its application to rock varnish yield reliable results, (2) sample contamination can be recognized, and (3) determination of the age of the puquios rests upon testable available information; ex silentio arguments about the presence or absence of the puquios in the Nasca region before the Spanish conquest are inadequate for the resolution of the question.