Formative

Initial Formative: 2500-1800 BC

Early Formative: 1800-1200 BC

Middle Formative: 1200-800 BC

Late Formative: 800-250 BC

Final Formative: 250-50 BC

Onuki 1999:332 [Sequence only, no absolute dates], Shibata 2004:82 [Includes absolute dates]