A large portion of the industry is in the hands of two companies, one of which is the South American Gold and Platinum Company, of New York, a Lewisohn company, which has absorbed the interests of the above-mentioned Anglo-Colombian Development Company, Ltd., the Gold Fields American Development Company, Ltd., and Johnson, Matthey & Co., Ltd., of London. The second company—the British Platinum and Gold Corporation, Ltd.—has recently amalgamated with the Paris (Transvaal) Gold Mines, Ltd., taking in the latter’s interests on the Opogodo and other places. The question of transporting platinum concentrate to the coast is not a matter of much difficulty, as the Atrato River is navigable as far as Quibdo, and the San Juan can be ascended by vessels of moderate draught for over 140 miles inland. An estimate of average working costs appears to be 6_d._ per c. yd. for dredging, and 3_d._ for hydraulicking[87]. In 1917 new platiniferous deposits were discovered in the Caceres district, between the Cauca and Nechi Rivers, in the department of Antioquia. The mineralized area extends along the Caceri River, a distance of 14¼ miles, the width at the north end being 1¼ miles, and 300 ft. at the southern extremity [10] p. 545. ECUADOR Platinum occurs, in association with the gold obtained from steam gravels, in the area covered by the Rivers Bogota, Cachabi, Uimbi, Santiago and Cayapas, but it has not so far been found in sufficient quantities to be of economic importance. Dredging has been employed in mining these deposits, but does not appear to have been a success, and operations are now largely confined to native washings[88]. FRENCH GUIANA Platiniferous gold-bearing sands are found in the Aporuague River, the metal, according to an analysis by A. Danmer, having the following composition in percentages: platinum, 41·96; gold, 18·18; silver, 18·39; copper, 20·56[89]. WORLD MAP OF PLATINUM DEPOSITS [Illustration: MAP SHOWING THE PLATINUM-BEARING DISTRICTS REFERRED TO IN THE TEXT. (British Empire and Protectorates shaded.) ] REFERENCES TO LITERATURE ON THE PLATINUM METALS ----- Footnote 1: Lindgren, W.: “Platinum and Allied Metals,” _U.S. Geol. Surv., Min. Res. of U.S._, 1911. Footnote 2: Thomas and MacAlister: _The Geology of Ore Deposits_, London, 1909. Footnote 3: Gowland, W.: _Metallurgy of Non-Ferrous Metals_, London, 1918. Footnote 4: Dunstan, B.: _Queensland Govt. Min. Journ._, 1917, =18=. Footnote 5: Lindgren, W.: “Platinum and Allied Metals,” _U.S. Geol. Surv., Min. Res. of U.S._, 1910. Footnote 6: Rose, T. K.: “Electrolytic Refining of Gold,” _Trans. Inst. Min. and Met._, 1914–15, =24=, p. 45. Footnote 7: Hill, Jas. M.: “The Platinum Situation,” _Eng. Min. Journ._, July 26, 1919. Footnote 8: Hautpick, E. de: _Mining Journ._, Feb. 1, 1913. Footnote 9: _Mineral Industry_, 1916, =25=.