Copper is next to gold in frequency of occurrence. Some of the best deposits have been found in the commune of San Cristobal, province of Santo Domingo. A company working lodes at Mount Mateo on the Nigua River, encountered ore yielding as high as 33 per cent of copper. On the Jaina River near the ruins of Buenaventura, I have seen promising ledges of copper ore. Copper carbonates predominated, the green ore known as malachite and the beautiful blue ore azurite were quite common, and white quartz, which on being broken showed little specks of native copper, was also to be found. The asperity of the region, the absence of roads and the uncertainty as to the extent of these deposits caused the attempts at working them to be but feeble until recently, when extensive works of development were undertaken in the vicinity. Copper veins have also been reported in the mountains of the commune of Bani, province of Santo Domingo; in the communes of Cotui and Bonao, province of La Vega; in the canton of Moncion, province of Monte Cristi; in the commune of San Juan de la Maguana, province of Azua, and at a number of other places. Iron is reported in large quantities in various parts of the country. The largest deposit so far known is on the banks of the Maimon River in the municipality of Cotui, being a bed of black magnetic oxide of iron, nine miles long. It is said to be excellent in quality and inexhaustible in quantity. The difficulties of transportation in this case could be obviated by the canalization of the river to its confluence with the Yuna River, so as to make it navigable for small boats. Iron ore has been discovered on the slope of Mt. Isabel de Torres behind the city of Puerto Plata, limonite deposits at various places in Santo Domingo province, and a rich black iron oxide on the upper Ozama River. A layer of iron pyrites extending from Los Llanos all the way to Sabana la Mar was believed by its discoverers to be a gold mine. The central ridge of Santo Domingo is part of the same mountain chain which extends through Santiago province in Cuba where enormous quantities of iron are produced, and it is not improbable that some of the Dominican mines will be found to pay.