Concurrent with the shift of Olmec political power from San Lorenzo, Veracruz, to La Venta, Tabasco, around 1000 B.C., widely distributed Olmec-style ceramics fade from the archaeological record, to be replaced by fine, small-scale carvings in stone, especially blue-green jadeite and serpentine. Incised jewelry, so-called “spoons,” masklike faces, and complexly modeled animal, human, and supernatural figures, all of Middle Formative date (1000–500 B.C.) and carved in Olmec style, have been discovered throughout most of Mesoamerica, from Costa Rica to the central Mexican Highlands to the southwest Mexican coast in the present-day state of Guerrero.
"Acquisitions of the Princeton University Art Museum 2012," Record of the Princeton University Art Museum 71/72 (2012-13): p. 105-132.
Gillett G. Griffin, "Olmec Forms and Materials Found in Central Guerrero," in The Olmec and Their Neighbors: Essays in Memory of Matthew W. Stirling, eds. Michael D. Coe, David C. Grove, Elizabeth P. Benson (Washington, D.C.: Dumburton Oaks Research Library and Collections, 1981).