The prospecting has generally been confined to the more accessible regions and nothing is known of the mountain valleys in the interior. The mineral deposits discovered have been of sufficient richness to cause the formation of mining companies for their development or further investigation. I do not, however, know of a single case where prospectors or mining companies have ever made expenses. The cause of failure has most frequently been the lack of transportation facilities in the island, on account of which the cost of carrying the ore to a place where it might be reduced became prohibitive. Sometimes enterprises failed because the deposit turned out to be too small, sometimes because the ore did not keep up to the standard, and not infrequently mining companies fell by the wayside because of bad management. Enough evidence of mineral wealth has been found to justify the belief that workable deposits do exist, and to warrant careful further investigation, especially as the means of communication are extended. The metals most frequently found are gold, copper and iron. Veins of auriferous quartz are found throughout the central chain, the richest lodes being encountered in metamorphic rocks near crystalline formations. The metal is most abundant in placers formed in the river beds. Such placers are common in the Jaina River and its tributaries in the province of Santo Domingo; in Bonao creek in Seibo province; and in the Verde River, the streams of Sabaneta and a number of other streams of the Cibao. On the upper Jaina and on the Verde River there are still persons who make their living by washing gold from the river sands. Hydraulic mining was attempted in Santiago province, but after the construction of an expensive canal the project was abandoned. Under the liberal mining law mining privileges have in recent years been granted for gold mines reported at numerous places in the communes of San Jose de las Matas, San Cristobal, Janico, San Juan de la Maguana, Sabaneta and others. Prof. William P. Black, one of the scientists accompanying the United States Commission of Inquiry in 1871, reported: "There is a very considerable extent of gold-bearing country in the interior and gold is washed from the rivers at various points. It is found along the Jaina, upon the Verde, and upon the Yaque and its tributaries, and doubtless upon the large rivers of the interior. Some portions of the gold fields were worked anciently by the Spaniards and Indians. There are doubtless many gold deposits, not only along the bed of rivers, but on the hills, which have never been worked, and there probably is considerable gold remaining among the old workings. The appearance of the soil and rocks is such as to justify the labor and expense of carefully prospecting the gold region."