Coal mines found in the Samana peninsula produced a kind of lignite which proved of little commercial value and gave rise to the belief that the Republic's coal deposits had not emerged from the formative period. Later investigations show that while there is considerable undeveloped lignite, coal suitable for fuel is not wanting. Small coal deposits have been discovered in the Cibao Valley, between the central and the northern mountain chain, in the province of Pacificador and that of Santiago. Anthracite coal found at Tamboril, near the city of Santiago, was used to run a small motor exhibited at an industrial fair in Santiago in 1903. In the commune of Altamira, province of Puerto Plata, lignite and anthracite beds have been discovered, and traces of anthracite have also been found in San Cristobal commune, and in the petroleum region of Azua. In the central mountain chain a valuable coal deposit has been found on the Haitian side and similar beds may be expected in Santo Domingo. Silver has been discovered at Tanci, near Yasica, in the commune of Puerto Plata. The old chronicles refer to silver mines at Jarabacoa and Cotui in La Vega province, also to others near Santiago, near Higuey and on the Jaina River. Platinum occurs at Jarabacoa, traces of quicksilver have been found near Santiago, Banica and San Cristobal, and tin in Seibo and Higuey. Rock salt is found near Neiba in inexhaustible quantities, there being several hills of native salt covered with a thin layer of soil. The fact that the waters of Lake Enriquillo are saltier than the sea is attributed by some to a deposit of this kind. The salt is so pure that it does not attract moisture and deliquesce. The isolation of the district has been an obstacle to the development of the salt mines, but there is a project for the building of a railroad to the port of Barahona. Part of the salt used in the island comes from salt ponds near Azua, where salt is obtained from sea water by solar evaporation. On a hill at the confluence of the Jimenoa and the Yaque del Norte an alum deposit reaches the surface and the natives gather alum which they sell in Santiago City. A deposit of amber having been reported in the Cibao a company was formed several years ago for its development, but as the company did nothing, so far as known, except issue stock, and no part of the untold millions which were affirmed to be within easy reach has materialized, the deposit is not regarded as possessing commercial value.