Unnamed 20-11

COX, DENNIS P., AND BRIGGS, REGINALD P., 1973, METALLOGENIC MAP OF PUERTO RICO: U.S. GEOLOGICAL SURVEY, MISCELLANEOUS GEOLOGIC INVESTIGATIONS MAP I-721, ACCOMPANIED BY EXPLANATORY PAMPHLET, 6 P.COX, D. P., MARVIN, R. F., M'GONIGLE, J. W., MCINTYRE, D. H., AND ROGERS, C. L., 1977, POTASSIUM-ARGON GEOCHRONOLOGY OF SOME METAMORPHIC, IGNEOUS, AND HYDROTHERMAL EVENTS IN PUERTO RICO AND THE VIRGIN ISLANDS: U.S. GEOLOGICAL SURVEY JOUR. RESEARCH, VOL. 5, NO. 6, P. 689-703.BERRYHILL, H. L., JR., 1965, GEOLOGY OF THE CIALES QUADRANGLE, PUERTO RICO: U.S. GEOLOGICAL SURVEY BULL. 1184, 116 P.