The muds, the analyses of which are reported in this paper, were collected in September 1879, during the laying of a cable between Marseilles and Algiers by the India Rubber, Gutta-Percha, and Telegraph Works Company, Limited, of Silvertown, the ship employed being the s.s. “Dacia.” The numbers of the samples are those which were affixed to them on board ship. Nos. 31 to 43 are all from localities lying near the African Coast; Nos. 45 and 46 are from positions between the African Coast and the Balearic Bank. Nos. 64 and 65 are from the Balearic Bank, and Nos. 86 to 89 are from the Gulf of Lyons. The positions and depths are collected in Table I.