A Mesoamerican Civilization: Dumbarton Oaks Conference on the Olmec . Washington, D.C., 1967. Elizabeth P. Benson, Ed. Dumbarton Oaks Research Library and Collection, Washington, 1968. xii + 186 pp., illus. $7.50.; America's First Civilization . Michael D. Coe. Richard B. Woodbury, consultant. Published by American Heritage, New York, 1968, in association with the Smithsonian Institution (distributor, Van Nostrand, Princeton, N. J.). 160 pp., illus. $4.95. Smithsonian Library.