The mineral resources of an area of 40,000 sq km, principally in the Department of Antioquia, but including small parts of the Departments of Caldas, Cordoba, Risaralda, and Tolima,were investigated during the period 1964-68. The area is designated Zone II by the Colombian Inventario Minero Nacional(IMN). The geology of approximately 45 percent of this area, or 18,000 sq km, has been mapped by IMN. Zone II has been a gold producer for centuries, and still produces 75 percent of Colombia's gold. Silver is recovered as a byproduct. Ferruginous laterites have been investigated as potential sources of iron ore but are not commercially exploitable. Nickeliferous laterite on serpentinite near Ure in the extreme northwest corner of the Zone is potentially exploitable, although less promising than similar laterites at Cerro Matoso, north of the Zone boundary. Known deposits of mercury, chromium, manganese, and copper are small and have limited economic potential. Cement-raw materials are important among nonmetallic resources, and four companies are engaged in the manufacture of portland cement. The eastern half of Zone II contains large carbonate rock reserves, but poor accessibility is a handicap to greater development at present. Dolomite near Arnalfi is quarried for the glass-making and other industries. Clay saprolite is abundant and widely used in making brick and tiles in ***' small backyard kilns. Kaolin of good quality near La Uni6n is used by the ceramic industry. Subbituminous coal beds of Tertiary age are , \ * ' ' ' ' $ k an important resource in the western part of the zone and have good I ' * 'V;< ** potential for greater development. Aggregate materials for cdn*truction ,t-: t ,; are varied and abundant. Deposits of sodic feldspar, talc, decorative stone, and silica are exploited on a small scale. Chrysotile asbestos ' "-" r \\.^ .-^t.;.-d eposits north of Campamento are being developed to supply fiber foe ' vV. __. Colombia's thriving asbestos-cement industry, which is presently dependent upon imported fiber. Wollastonitie and andalusite are-potential