Published online by Cambridge University Press: 02 June 2017
New data from two sites in the municipality of San Blas, Nayarit, indicate that the practice of pecking petroglyphs in West Mexico is older than it has been possible to establish in previous studies. Petroglyphs at the La Coba site appear firmly dated to the Los Cocos phase (A.D. 200-600), and petroglyphs at the El Conchal site seem attributable to the Early Ixtlan phase (300 B.C.-A.D. 200) occupation. Hypotheses are offered regarding stylistic evolution of the pecked designs and their interpretation.