Chemical studies on the ultimate composition of plants, animals, and sediments of the marine environment have revealed the existence of high concentrations of such minor oceanic constituents as zirconium, titanium, and thallium. The fact that some of these elements have not yet been detected in sea water has made these observations all the more striking. It is inviting, therefore, to explore the paths of trace metallic elements through the various geospheres of the earth’s surface. The task of delimiting chemically the marine milieu is beset with complexities. First of all, although more than 90 per cent of marine waters exists at depths greater than 1000 meters, the vast majority of chemical investigations have been concerned with waters of shallower depths. For example, in a recent survey of published iron analyses of oceanic waters undertaken by the author, only 4 of the 39 investigations presented data for waters taken at depths greater than 1000 meters. The concentration of certain elements appears to vary by factors greater than two orders of magnitude. In the analyses cited above, the iron content in Japanese coastal waters shows a range of 0 to 800 mg/liter. Finally, many reported concentrations fail to differentiate elements between the solid phases of either organic or inorganic origin and the dissolved phase. Although the experimental separation of the solid and liquid phases is arbitrary, as it is somewhat dependent upon the porosity of the filter employed, such distinctions are of utmost importance. Table 1 presents the marine abundances compiled critically...